1 \input texinfo @c -*-texinfo-*-
3 @setfilename openocd.info
4 @settitle OpenOCD User's Guide
5 @dircategory Development
7 * OpenOCD: (openocd). OpenOCD User's Guide
16 This User's Guide documents
17 release @value{VERSION},
18 dated @value{UPDATED},
19 of the Open On-Chip Debugger (OpenOCD).
22 @item Copyright @copyright{} 2008 The OpenOCD Project
23 @item Copyright @copyright{} 2007-2008 Spencer Oliver @email{spen@@spen-soft.co.uk}
24 @item Copyright @copyright{} 2008-2010 Oyvind Harboe @email{oyvind.harboe@@zylin.com}
25 @item Copyright @copyright{} 2008 Duane Ellis @email{openocd@@duaneellis.com}
26 @item Copyright @copyright{} 2009-2010 David Brownell
30 Permission is granted to copy, distribute and/or modify this document
31 under the terms of the GNU Free Documentation License, Version 1.2 or
32 any later version published by the Free Software Foundation; with no
33 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
34 Texts. A copy of the license is included in the section entitled ``GNU
35 Free Documentation License''.
40 @titlefont{@emph{Open On-Chip Debugger:}}
42 @title OpenOCD User's Guide
43 @subtitle for release @value{VERSION}
44 @subtitle @value{UPDATED}
47 @vskip 0pt plus 1filll
56 @top OpenOCD User's Guide
62 * About:: About OpenOCD
63 * Developers:: OpenOCD Developer Resources
64 * Debug Adapter Hardware:: Debug Adapter Hardware
65 * About Jim-Tcl:: About Jim-Tcl
66 * Running:: Running OpenOCD
67 * OpenOCD Project Setup:: OpenOCD Project Setup
68 * Config File Guidelines:: Config File Guidelines
69 * Daemon Configuration:: Daemon Configuration
70 * Debug Adapter Configuration:: Debug Adapter Configuration
71 * Reset Configuration:: Reset Configuration
72 * TAP Declaration:: TAP Declaration
73 * CPU Configuration:: CPU Configuration
74 * Flash Commands:: Flash Commands
75 * Flash Programming:: Flash Programming
76 * NAND Flash Commands:: NAND Flash Commands
77 * PLD/FPGA Commands:: PLD/FPGA Commands
78 * General Commands:: General Commands
79 * Architecture and Core Commands:: Architecture and Core Commands
80 * JTAG Commands:: JTAG Commands
81 * Boundary Scan Commands:: Boundary Scan Commands
83 * GDB and OpenOCD:: Using GDB and OpenOCD
84 * Tcl Scripting API:: Tcl Scripting API
85 * FAQ:: Frequently Asked Questions
86 * Tcl Crash Course:: Tcl Crash Course
87 * License:: GNU Free Documentation License
89 @comment DO NOT use the plain word ``Index'', reason: CYGWIN filename
90 @comment case issue with ``Index.html'' and ``index.html''
91 @comment Occurs when creating ``--html --no-split'' output
92 @comment This fix is based on: http://sourceware.org/ml/binutils/2006-05/msg00215.html
93 * OpenOCD Concept Index:: Concept Index
94 * Command and Driver Index:: Command and Driver Index
101 OpenOCD was created by Dominic Rath as part of a diploma thesis written at the
102 University of Applied Sciences Augsburg (@uref{http://www.fh-augsburg.de}).
103 Since that time, the project has grown into an active open-source project,
104 supported by a diverse community of software and hardware developers from
107 @section What is OpenOCD?
111 The Open On-Chip Debugger (OpenOCD) aims to provide debugging,
112 in-system programming and boundary-scan testing for embedded target
115 It does so with the assistance of a @dfn{debug adapter}, which is
116 a small hardware module which helps provide the right kind of
117 electrical signaling to the target being debugged. These are
118 required since the debug host (on which OpenOCD runs) won't
119 usually have native support for such signaling, or the connector
120 needed to hook up to the target.
122 Such debug adapters support one or more @dfn{transport} protocols,
123 each of which involves different electrical signaling (and uses
124 different messaging protocols on top of that signaling). There
125 are many types of debug adapter, and little uniformity in what
126 they are called. (There are also product naming differences.)
128 These adapters are sometimes packaged as discrete dongles, which
129 may generically be called @dfn{hardware interface dongles}.
130 Some development boards also integrate them directly, which may
131 let the development board can be directly connected to the debug
132 host over USB (and sometimes also to power it over USB).
134 For example, a @dfn{JTAG Adapter} supports JTAG
135 signaling, and is used to communicate
136 with JTAG (IEEE 1149.1) compliant TAPs on your target board.
137 A @dfn{TAP} is a ``Test Access Port'', a module which processes
138 special instructions and data. TAPs are daisy-chained within and
139 between chips and boards. JTAG supports debugging and boundary
142 There are also @dfn{SWD Adapters} that support Serial Wire Debug (SWD)
143 signaling to communicate with some newer ARM cores, as well as debug
144 adapters which support both JTAG and SWD transports. SWD only supports
145 debugging, whereas JTAG also supports boundary scan operations.
147 For some chips, there are also @dfn{Programming Adapters} supporting
148 special transports used only to write code to flash memory, without
149 support for on-chip debugging or boundary scan.
150 (At this writing, OpenOCD does not support such non-debug adapters.)
153 @b{Dongles:} OpenOCD currently supports many types of hardware dongles: USB
154 based, parallel port based, and other standalone boxes that run
155 OpenOCD internally. @xref{Debug Adapter Hardware}.
157 @b{GDB Debug:} It allows ARM7 (ARM7TDMI and ARM720t), ARM9 (ARM920T,
158 ARM922T, ARM926EJ--S, ARM966E--S), XScale (PXA25x, IXP42x) and
159 Cortex-M3 (Stellaris LM3, ST STM32 and Energy Micro EFM32) based cores to be
160 debugged via the GDB protocol.
162 @b{Flash Programing:} Flash writing is supported for external CFI
163 compatible NOR flashes (Intel and AMD/Spansion command set) and several
164 internal flashes (LPC1700, LPC1800, LPC2000, LPC4300, AT91SAM7, AT91SAM3U,
165 STR7x, STR9x, LM3, STM32x and EFM32). Preliminary support for various NAND flash
166 controllers (LPC3180, Orion, S3C24xx, more) controller is included.
168 @section OpenOCD Web Site
170 The OpenOCD web site provides the latest public news from the community:
172 @uref{http://openocd.sourceforge.net/}
174 @section Latest User's Guide:
176 The user's guide you are now reading may not be the latest one
177 available. A version for more recent code may be available.
178 Its HTML form is published regularly at:
180 @uref{http://openocd.sourceforge.net/doc/html/index.html}
182 PDF form is likewise published at:
184 @uref{http://openocd.sourceforge.net/doc/pdf/openocd.pdf}
186 @section OpenOCD User's Forum
188 There is an OpenOCD forum (phpBB) hosted by SparkFun,
189 which might be helpful to you. Note that if you want
190 anything to come to the attention of developers, you
191 should post it to the OpenOCD Developer Mailing List
192 instead of this forum.
194 @uref{http://forum.sparkfun.com/viewforum.php?f=18}
196 @section OpenOCD User's Mailing List
198 The OpenOCD User Mailing List provides the primary means of
199 communication between users:
201 @uref{https://lists.sourceforge.net/mailman/listinfo/openocd-user}
205 Support can also be found on irc:
206 @uref{irc://irc.freenode.net/openocd}
209 @chapter OpenOCD Developer Resources
212 If you are interested in improving the state of OpenOCD's debugging and
213 testing support, new contributions will be welcome. Motivated developers
214 can produce new target, flash or interface drivers, improve the
215 documentation, as well as more conventional bug fixes and enhancements.
217 The resources in this chapter are available for developers wishing to explore
218 or expand the OpenOCD source code.
220 @section OpenOCD GIT Repository
222 During the 0.3.x release cycle, OpenOCD switched from Subversion to
223 a GIT repository hosted at SourceForge. The repository URL is:
225 @uref{git://git.code.sf.net/p/openocd/code}
229 @uref{http://git.code.sf.net/p/openocd/code}
231 You may prefer to use a mirror and the HTTP protocol:
233 @uref{http://repo.or.cz/r/openocd.git}
235 With standard GIT tools, use @command{git clone} to initialize
236 a local repository, and @command{git pull} to update it.
237 There are also gitweb pages letting you browse the repository
238 with a web browser, or download arbitrary snapshots without
239 needing a GIT client:
241 @uref{http://repo.or.cz/w/openocd.git}
243 The @file{README} file contains the instructions for building the project
244 from the repository or a snapshot.
246 Developers that want to contribute patches to the OpenOCD system are
247 @b{strongly} encouraged to work against mainline.
248 Patches created against older versions may require additional
249 work from their submitter in order to be updated for newer releases.
251 @section Doxygen Developer Manual
253 During the 0.2.x release cycle, the OpenOCD project began
254 providing a Doxygen reference manual. This document contains more
255 technical information about the software internals, development
256 processes, and similar documentation:
258 @uref{http://openocd.sourceforge.net/doc/doxygen/html/index.html}
260 This document is a work-in-progress, but contributions would be welcome
261 to fill in the gaps. All of the source files are provided in-tree,
262 listed in the Doxyfile configuration in the top of the source tree.
264 @section OpenOCD Developer Mailing List
266 The OpenOCD Developer Mailing List provides the primary means of
267 communication between developers:
269 @uref{https://lists.sourceforge.net/mailman/listinfo/openocd-devel}
271 Discuss and submit patches to this list.
272 The @file{HACKING} file contains basic information about how
275 @section OpenOCD Bug Database
277 During the 0.4.x release cycle the OpenOCD project team began
278 using Trac for its bug database:
280 @uref{https://sourceforge.net/apps/trac/openocd}
283 @node Debug Adapter Hardware
284 @chapter Debug Adapter Hardware
293 Defined: @b{dongle}: A small device that plugins into a computer and serves as
294 an adapter .... [snip]
296 In the OpenOCD case, this generally refers to @b{a small adapter} that
297 attaches to your computer via USB or the Parallel Printer Port. One
298 exception is the Zylin ZY1000, packaged as a small box you attach via
299 an ethernet cable. The Zylin ZY1000 has the advantage that it does not
300 require any drivers to be installed on the developer PC. It also has
301 a built in web interface. It supports RTCK/RCLK or adaptive clocking
302 and has a built in relay to power cycle targets remotely.
305 @section Choosing a Dongle
307 There are several things you should keep in mind when choosing a dongle.
310 @item @b{Transport} Does it support the kind of communication that you need?
311 OpenOCD focusses mostly on JTAG. Your version may also support
312 other ways to communicate with target devices.
313 @item @b{Voltage} What voltage is your target - 1.8, 2.8, 3.3, or 5V?
314 Does your dongle support it? You might need a level converter.
315 @item @b{Pinout} What pinout does your target board use?
316 Does your dongle support it? You may be able to use jumper
317 wires, or an "octopus" connector, to convert pinouts.
318 @item @b{Connection} Does your computer have the USB, printer, or
319 Ethernet port needed?
320 @item @b{RTCK} Do you expect to use it with ARM chips and boards with
321 RTCK support? Also known as ``adaptive clocking''
324 @section Stand-alone JTAG Probe
326 The ZY1000 from Ultimate Solutions is technically not a dongle but a
327 stand-alone JTAG probe that unlikemost dongles doesn’t require any drivers
328 running on the developers host computer.
329 Once installed on a network using DHCP or a static IP assignment, users can
330 access the ZY1000 probe locally or remotely from any host with access to the
331 IP address assigned to the probe.
332 The ZY1000 provides an intuitive web interface with direct access to the
334 Users may also run a GDBSERVER directly on the ZY1000 to take full advantage
335 of GCC & GDB to debug any distribution of embedded Linux or NetBSD running on
337 The ZY1000 supports RTCK & RCLK or adaptive clocking and has a built-in relay
338 to power cycle the target remotely.
340 For more information, visit:
342 @b{ZY1000} See: @url{http://www.ultsol.com/index.php/component/content/article/8/33-zylin-zy1000-jtag-probe}
344 @section USB FT2232 Based
346 There are many USB JTAG dongles on the market, many of them are based
347 on a chip from ``Future Technology Devices International'' (FTDI)
348 known as the FTDI FT2232; this is a USB full speed (12 Mbps) chip.
349 See: @url{http://www.ftdichip.com} for more information.
350 In summer 2009, USB high speed (480 Mbps) versions of these FTDI
351 chips are starting to become available in JTAG adapters. Around 2012 a new
352 variant appeared - FT232H - this is a single-channel version of FT2232H.
353 (Adapters using those high speed FT2232H or FT232H chips may support adaptive
356 The FT2232 chips are flexible enough to support some other
357 transport options, such as SWD or the SPI variants used to
358 program some chips. They have two communications channels,
359 and one can be used for a UART adapter at the same time the
360 other one is used to provide a debug adapter.
362 Also, some development boards integrate an FT2232 chip to serve as
363 a built-in low cost debug adapter and usb-to-serial solution.
367 @* Link @url{http://elk.informatik.fh-augsburg.de/hhweb/doc/openocd/usbjtag/usbjtag.html}
369 @* See: @url{http://www.amontec.com/jtagkey.shtml}
371 @* See: @url{http://www.amontec.com/jtagkey2.shtml}
373 @* See: @url{http://www.oocdlink.com} By Joern Kaipf
375 @* See: @url{http://www.signalyzer.com}
376 @item @b{Stellaris Eval Boards}
377 @* See: @url{http://www.ti.com} - The Stellaris eval boards
378 bundle FT2232-based JTAG and SWD support, which can be used to debug
379 the Stellaris chips. Using separate JTAG adapters is optional.
380 These boards can also be used in a "pass through" mode as JTAG adapters
381 to other target boards, disabling the Stellaris chip.
382 @item @b{TI/Luminary ICDI}
383 @* See: @url{http://www.ti.com} - TI/Luminary In-Circuit Debug
384 Interface (ICDI) Boards are included in Stellaris LM3S9B9x
385 Evaluation Kits. Like the non-detachable FT2232 support on the other
386 Stellaris eval boards, they can be used to debug other target boards.
387 @item @b{olimex-jtag}
388 @* See: @url{http://www.olimex.com}
389 @item @b{Flyswatter/Flyswatter2}
390 @* See: @url{http://www.tincantools.com}
391 @item @b{turtelizer2}
393 @uref{http://www.ethernut.de/en/hardware/turtelizer/index.html, Turtelizer 2}, or
394 @url{http://www.ethernut.de}
396 @* Link: @url{http://www.hitex.com/index.php?id=383}
398 @* Link @url{http://www.hitex.com/stm32-stick}
399 @item @b{axm0432_jtag}
400 @* Axiom AXM-0432 Link @url{http://www.axman.com} - NOTE: This JTAG does not appear
401 to be available anymore as of April 2012.
403 @* Link @url{http://www.hitex.com/index.php?id=cortino}
404 @item @b{dlp-usb1232h}
405 @* Link @url{http://www.dlpdesign.com/usb/usb1232h.shtml}
406 @item @b{digilent-hs1}
407 @* Link @url{http://www.digilentinc.com/Products/Detail.cfm?Prod=JTAG-HS1}
409 @* Link @url{http://code.google.com/p/opendous/wiki/JTAG} FT2232H-based
411 @item @b{JTAG-lock-pick Tiny 2}
412 @* Link @url{http://www.distortec.com/jtag-lock-pick-tiny-2} FT232H-based
415 @* Link: @url{http://shop.gateworks.com/index.php?route=product/product&path=70_80&product_id=64}
419 @section USB-JTAG / Altera USB-Blaster compatibles
421 These devices also show up as FTDI devices, but are not
422 protocol-compatible with the FT2232 devices. They are, however,
423 protocol-compatible among themselves. USB-JTAG devices typically consist
424 of a FT245 followed by a CPLD that understands a particular protocol,
425 or emulate this protocol using some other hardware.
427 They may appear under different USB VID/PID depending on the particular
428 product. The driver can be configured to search for any VID/PID pair
429 (see the section on driver commands).
432 @item @b{USB-JTAG} Kolja Waschk's USB Blaster-compatible adapter
433 @* Link: @url{http://ixo-jtag.sourceforge.net/}
434 @item @b{Altera USB-Blaster}
435 @* Link: @url{http://www.altera.com/literature/ug/ug_usb_blstr.pdf}
438 @section USB JLINK based
439 There are several OEM versions of the Segger @b{JLINK} adapter. It is
440 an example of a micro controller based JTAG adapter, it uses an
441 AT91SAM764 internally.
444 @item @b{ATMEL SAMICE} Only works with ATMEL chips!
445 @* Link: @url{http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3892}
446 @item @b{SEGGER JLINK}
447 @* Link: @url{http://www.segger.com/jlink.html}
449 @* Link: @url{http://www.iar.com/en/products/hardware-debug-probes/iar-j-link/}
452 @section USB RLINK based
453 Raisonance has an adapter called @b{RLink}. It exists in a stripped-down form on the STM32 Primer,
454 permanently attached to the JTAG lines. It also exists on the STM32 Primer2, but that is wired for
455 SWD and not JTAG, thus not supported.
458 @item @b{Raisonance RLink}
459 @* Link: @url{http://www.mcu-raisonance.com/~rlink-debugger-programmer__microcontrollers__tool~tool__T018:4cn9ziz4bnx6.html}
460 @item @b{STM32 Primer}
461 @* Link: @url{http://www.stm32circle.com/resources/stm32primer.php}
462 @item @b{STM32 Primer2}
463 @* Link: @url{http://www.stm32circle.com/resources/stm32primer2.php}
466 @section USB ST-LINK based
467 ST Micro has an adapter called @b{ST-LINK}.
468 They only work with ST Micro chips, notably STM32 and STM8.
472 @* This is available standalone and as part of some kits, eg. STM32VLDISCOVERY.
473 @* Link: @url{http://www.st.com/internet/evalboard/product/219866.jsp}
475 @* This is available standalone and as part of some kits, eg. STM32F4DISCOVERY.
476 @* Link: @url{http://www.st.com/internet/evalboard/product/251168.jsp}
479 For info the original ST-LINK enumerates using the mass storage usb class, however
480 it's implementation is completely broken. The result is this causes issues under linux.
481 The simplest solution is to get linux to ignore the ST-LINK using one of the following methods:
483 @item modprobe -r usb-storage && modprobe usb-storage quirks=483:3744:i
484 @item add "options usb-storage quirks=483:3744:i" to /etc/modprobe.conf
487 @section USB TI/Stellaris ICDI based
488 Texas Instruments has an adapter called @b{ICDI}.
489 It is not to be confused with the FTDI based adapters that were originally fitted to their
490 evaluation boards. This is the adapter fitted to the Stellaris LaunchPad.
495 @* Link: @url{http://shop.embedded-projects.net/} - which uses an Atmel MEGA32 and a UBN9604
497 @item @b{USB - Presto}
498 @* Link: @url{http://tools.asix.net/prg_presto.htm}
500 @item @b{Versaloon-Link}
501 @* Link: @url{http://www.versaloon.com}
503 @item @b{ARM-JTAG-EW}
504 @* Link: @url{http://www.olimex.com/dev/arm-jtag-ew.html}
507 @* Link: @url{http://dangerousprototypes.com/bus-pirate-manual/}
510 @* Link: @url{http://code.google.com/p/opendous-jtag/} - which uses an AT90USB162
513 @* Link: @url{http://code.google.com/p/estick-jtag/}
515 @item @b{Keil ULINK v1}
516 @* Link: @url{http://www.keil.com/ulink1/}
519 @section IBM PC Parallel Printer Port Based
521 The two well known ``JTAG Parallel Ports'' cables are the Xilnx DLC5
522 and the Macraigor Wiggler. There are many clones and variations of
525 Note that parallel ports are becoming much less common, so if you
526 have the choice you should probably avoid these adapters in favor
531 @item @b{Wiggler} - There are many clones of this.
532 @* Link: @url{http://www.macraigor.com/wiggler.htm}
534 @item @b{DLC5} - From XILINX - There are many clones of this
535 @* Link: Search the web for: ``XILINX DLC5'' - it is no longer
536 produced, PDF schematics are easily found and it is easy to make.
538 @item @b{Amontec - JTAG Accelerator}
539 @* Link: @url{http://www.amontec.com/jtag_accelerator.shtml}
542 @* Link: @url{http://www.ccac.rwth-aachen.de/~michaels/index.php/hardware/armjtag}
544 @item @b{Wiggler_ntrst_inverted}
545 @* Yet another variation - See the source code, src/jtag/parport.c
547 @item @b{old_amt_wiggler}
548 @* Unknown - probably not on the market today
551 @* Link: Most likely @url{http://www.olimex.com/dev/arm-jtag.html} [another wiggler clone]
554 @* Link: @url{http://www.amontec.com/chameleon.shtml}
560 @* ispDownload from Lattice Semiconductor
561 @url{http://www.latticesemi.com/lit/docs/@/devtools/dlcable.pdf}
564 @* From ST Microsystems;
565 @* Link: @url{http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/DM00039500.pdf}
573 @* An EP93xx based Linux machine using the GPIO pins directly.
576 @* Like the EP93xx - but an ATMEL AT91RM9200 based solution using the GPIO pins on the chip.
578 @item @b{bcm2835gpio}
579 @* A BCM2835-based board (e.g. Raspberry Pi) using the GPIO pins of the expansion header.
584 @chapter About Jim-Tcl
588 OpenOCD uses a small ``Tcl Interpreter'' known as Jim-Tcl.
589 This programming language provides a simple and extensible
592 All commands presented in this Guide are extensions to Jim-Tcl.
593 You can use them as simple commands, without needing to learn
594 much of anything about Tcl.
595 Alternatively, can write Tcl programs with them.
597 You can learn more about Jim at its website, @url{http://jim.berlios.de}.
598 There is an active and responsive community, get on the mailing list
599 if you have any questions. Jim-Tcl maintainers also lurk on the
600 OpenOCD mailing list.
603 @item @b{Jim vs. Tcl}
604 @* Jim-Tcl is a stripped down version of the well known Tcl language,
605 which can be found here: @url{http://www.tcl.tk}. Jim-Tcl has far
606 fewer features. Jim-Tcl is several dozens of .C files and .H files and
607 implements the basic Tcl command set. In contrast: Tcl 8.6 is a
608 4.2 MB .zip file containing 1540 files.
610 @item @b{Missing Features}
611 @* Our practice has been: Add/clone the real Tcl feature if/when
612 needed. We welcome Jim-Tcl improvements, not bloat. Also there
613 are a large number of optional Jim-Tcl features that are not
617 @* OpenOCD configuration scripts are Jim-Tcl Scripts. OpenOCD's
618 command interpreter today is a mixture of (newer)
619 Jim-Tcl commands, and (older) the orginal command interpreter.
622 @* At the OpenOCD telnet command line (or via the GDB monitor command) one
623 can type a Tcl for() loop, set variables, etc.
624 Some of the commands documented in this guide are implemented
625 as Tcl scripts, from a @file{startup.tcl} file internal to the server.
627 @item @b{Historical Note}
628 @* Jim-Tcl was introduced to OpenOCD in spring 2008. Fall 2010,
629 before OpenOCD 0.5 release OpenOCD switched to using Jim Tcl
630 as a git submodule, which greatly simplified upgrading Jim Tcl
631 to benefit from new features and bugfixes in Jim Tcl.
633 @item @b{Need a crash course in Tcl?}
634 @*@xref{Tcl Crash Course}.
639 @cindex command line options
641 @cindex directory search
643 Properly installing OpenOCD sets up your operating system to grant it access
644 to the debug adapters. On Linux, this usually involves installing a file
645 in @file{/etc/udev/rules.d,} so OpenOCD has permissions. MS-Windows needs
646 complex and confusing driver configuration for every peripheral. Such issues
647 are unique to each operating system, and are not detailed in this User's Guide.
649 Then later you will invoke the OpenOCD server, with various options to
650 tell it how each debug session should work.
651 The @option{--help} option shows:
655 --help | -h display this help
656 --version | -v display OpenOCD version
657 --file | -f use configuration file <name>
658 --search | -s dir to search for config files and scripts
659 --debug | -d set debug level <0-3>
660 --log_output | -l redirect log output to file <name>
661 --command | -c run <command>
664 If you don't give any @option{-f} or @option{-c} options,
665 OpenOCD tries to read the configuration file @file{openocd.cfg}.
666 To specify one or more different
667 configuration files, use @option{-f} options. For example:
670 openocd -f config1.cfg -f config2.cfg -f config3.cfg
673 Configuration files and scripts are searched for in
675 @item the current directory,
676 @item any search dir specified on the command line using the @option{-s} option,
677 @item any search dir specified using the @command{add_script_search_dir} command,
678 @item @file{$HOME/.openocd} (not on Windows),
679 @item the site wide script library @file{$pkgdatadir/site} and
680 @item the OpenOCD-supplied script library @file{$pkgdatadir/scripts}.
682 The first found file with a matching file name will be used.
685 Don't try to use configuration script names or paths which
686 include the "#" character. That character begins Tcl comments.
689 @section Simple setup, no customization
691 In the best case, you can use two scripts from one of the script
692 libraries, hook up your JTAG adapter, and start the server ... and
693 your JTAG setup will just work "out of the box". Always try to
694 start by reusing those scripts, but assume you'll need more
695 customization even if this works. @xref{OpenOCD Project Setup}.
697 If you find a script for your JTAG adapter, and for your board or
698 target, you may be able to hook up your JTAG adapter then start
702 openocd -f interface/ADAPTER.cfg -f board/MYBOARD.cfg
705 You might also need to configure which reset signals are present,
706 using @option{-c 'reset_config trst_and_srst'} or something similar.
707 If all goes well you'll see output something like
710 Open On-Chip Debugger 0.4.0 (2010-01-14-15:06)
711 For bug reports, read
712 http://openocd.sourceforge.net/doc/doxygen/bugs.html
713 Info : JTAG tap: lm3s.cpu tap/device found: 0x3ba00477
714 (mfg: 0x23b, part: 0xba00, ver: 0x3)
717 Seeing that "tap/device found" message, and no warnings, means
718 the JTAG communication is working. That's a key milestone, but
719 you'll probably need more project-specific setup.
721 @section What OpenOCD does as it starts
723 OpenOCD starts by processing the configuration commands provided
724 on the command line or, if there were no @option{-c command} or
725 @option{-f file.cfg} options given, in @file{openocd.cfg}.
726 @xref{configurationstage,,Configuration Stage}.
727 At the end of the configuration stage it verifies the JTAG scan
728 chain defined using those commands; your configuration should
729 ensure that this always succeeds.
730 Normally, OpenOCD then starts running as a daemon.
731 Alternatively, commands may be used to terminate the configuration
732 stage early, perform work (such as updating some flash memory),
733 and then shut down without acting as a daemon.
735 Once OpenOCD starts running as a daemon, it waits for connections from
736 clients (Telnet, GDB, Other) and processes the commands issued through
739 If you are having problems, you can enable internal debug messages via
740 the @option{-d} option.
742 Also it is possible to interleave Jim-Tcl commands w/config scripts using the
743 @option{-c} command line switch.
745 To enable debug output (when reporting problems or working on OpenOCD
746 itself), use the @option{-d} command line switch. This sets the
747 @option{debug_level} to "3", outputting the most information,
748 including debug messages. The default setting is "2", outputting only
749 informational messages, warnings and errors. You can also change this
750 setting from within a telnet or gdb session using @command{debug_level<n>}
751 (@pxref{debuglevel,,debug_level}).
753 You can redirect all output from the daemon to a file using the
754 @option{-l <logfile>} switch.
756 Note! OpenOCD will launch the GDB & telnet server even if it can not
757 establish a connection with the target. In general, it is possible for
758 the JTAG controller to be unresponsive until the target is set up
759 correctly via e.g. GDB monitor commands in a GDB init script.
761 @node OpenOCD Project Setup
762 @chapter OpenOCD Project Setup
764 To use OpenOCD with your development projects, you need to do more than
765 just connecting the JTAG adapter hardware (dongle) to your development board
766 and then starting the OpenOCD server.
767 You also need to configure that server so that it knows
768 about that adapter and board, and helps your work.
769 You may also want to connect OpenOCD to GDB, possibly
770 using Eclipse or some other GUI.
772 @section Hooking up the JTAG Adapter
774 Today's most common case is a dongle with a JTAG cable on one side
775 (such as a ribbon cable with a 10-pin or 20-pin IDC connector)
776 and a USB cable on the other.
777 Instead of USB, some cables use Ethernet;
778 older ones may use a PC parallel port, or even a serial port.
781 @item @emph{Start with power to your target board turned off},
782 and nothing connected to your JTAG adapter.
783 If you're particularly paranoid, unplug power to the board.
784 It's important to have the ground signal properly set up,
785 unless you are using a JTAG adapter which provides
786 galvanic isolation between the target board and the
789 @item @emph{Be sure it's the right kind of JTAG connector.}
790 If your dongle has a 20-pin ARM connector, you need some kind
791 of adapter (or octopus, see below) to hook it up to
792 boards using 14-pin or 10-pin connectors ... or to 20-pin
793 connectors which don't use ARM's pinout.
795 In the same vein, make sure the voltage levels are compatible.
796 Not all JTAG adapters have the level shifters needed to work
797 with 1.2 Volt boards.
799 @item @emph{Be certain the cable is properly oriented} or you might
800 damage your board. In most cases there are only two possible
801 ways to connect the cable.
802 Connect the JTAG cable from your adapter to the board.
803 Be sure it's firmly connected.
805 In the best case, the connector is keyed to physically
806 prevent you from inserting it wrong.
807 This is most often done using a slot on the board's male connector
808 housing, which must match a key on the JTAG cable's female connector.
809 If there's no housing, then you must look carefully and
810 make sure pin 1 on the cable hooks up to pin 1 on the board.
811 Ribbon cables are frequently all grey except for a wire on one
812 edge, which is red. The red wire is pin 1.
814 Sometimes dongles provide cables where one end is an ``octopus'' of
815 color coded single-wire connectors, instead of a connector block.
816 These are great when converting from one JTAG pinout to another,
817 but are tedious to set up.
818 Use these with connector pinout diagrams to help you match up the
819 adapter signals to the right board pins.
821 @item @emph{Connect the adapter's other end} once the JTAG cable is connected.
822 A USB, parallel, or serial port connector will go to the host which
823 you are using to run OpenOCD.
824 For Ethernet, consult the documentation and your network administrator.
826 For USB based JTAG adapters you have an easy sanity check at this point:
827 does the host operating system see the JTAG adapter? If that host is an
828 MS-Windows host, you'll need to install a driver before OpenOCD works.
830 @item @emph{Connect the adapter's power supply, if needed.}
831 This step is primarily for non-USB adapters,
832 but sometimes USB adapters need extra power.
834 @item @emph{Power up the target board.}
835 Unless you just let the magic smoke escape,
836 you're now ready to set up the OpenOCD server
837 so you can use JTAG to work with that board.
841 Talk with the OpenOCD server using
842 telnet (@code{telnet localhost 4444} on many systems) or GDB.
843 @xref{GDB and OpenOCD}.
845 @section Project Directory
847 There are many ways you can configure OpenOCD and start it up.
849 A simple way to organize them all involves keeping a
850 single directory for your work with a given board.
851 When you start OpenOCD from that directory,
852 it searches there first for configuration files, scripts,
853 files accessed through semihosting,
854 and for code you upload to the target board.
855 It is also the natural place to write files,
856 such as log files and data you download from the board.
858 @section Configuration Basics
860 There are two basic ways of configuring OpenOCD, and
861 a variety of ways you can mix them.
862 Think of the difference as just being how you start the server:
865 @item Many @option{-f file} or @option{-c command} options on the command line
866 @item No options, but a @dfn{user config file}
867 in the current directory named @file{openocd.cfg}
870 Here is an example @file{openocd.cfg} file for a setup
871 using a Signalyzer FT2232-based JTAG adapter to talk to
872 a board with an Atmel AT91SAM7X256 microcontroller:
875 source [find interface/signalyzer.cfg]
877 # GDB can also flash my flash!
878 gdb_memory_map enable
879 gdb_flash_program enable
881 source [find target/sam7x256.cfg]
884 Here is the command line equivalent of that configuration:
887 openocd -f interface/signalyzer.cfg \
888 -c "gdb_memory_map enable" \
889 -c "gdb_flash_program enable" \
890 -f target/sam7x256.cfg
893 You could wrap such long command lines in shell scripts,
894 each supporting a different development task.
895 One might re-flash the board with a specific firmware version.
896 Another might set up a particular debugging or run-time environment.
899 At this writing (October 2009) the command line method has
900 problems with how it treats variables.
901 For example, after @option{-c "set VAR value"}, or doing the
902 same in a script, the variable @var{VAR} will have no value
903 that can be tested in a later script.
906 Here we will focus on the simpler solution: one user config
907 file, including basic configuration plus any TCL procedures
908 to simplify your work.
910 @section User Config Files
911 @cindex config file, user
912 @cindex user config file
913 @cindex config file, overview
915 A user configuration file ties together all the parts of a project
917 One of the following will match your situation best:
920 @item Ideally almost everything comes from configuration files
921 provided by someone else.
922 For example, OpenOCD distributes a @file{scripts} directory
923 (probably in @file{/usr/share/openocd/scripts} on Linux).
924 Board and tool vendors can provide these too, as can individual
925 user sites; the @option{-s} command line option lets you say
926 where to find these files. (@xref{Running}.)
927 The AT91SAM7X256 example above works this way.
929 Three main types of non-user configuration file each have their
930 own subdirectory in the @file{scripts} directory:
933 @item @b{interface} -- one for each different debug adapter;
934 @item @b{board} -- one for each different board
935 @item @b{target} -- the chips which integrate CPUs and other JTAG TAPs
938 Best case: include just two files, and they handle everything else.
939 The first is an interface config file.
940 The second is board-specific, and it sets up the JTAG TAPs and
941 their GDB targets (by deferring to some @file{target.cfg} file),
942 declares all flash memory, and leaves you nothing to do except
946 source [find interface/olimex-jtag-tiny.cfg]
947 source [find board/csb337.cfg]
950 Boards with a single microcontroller often won't need more
951 than the target config file, as in the AT91SAM7X256 example.
952 That's because there is no external memory (flash, DDR RAM), and
953 the board differences are encapsulated by application code.
955 @item Maybe you don't know yet what your board looks like to JTAG.
956 Once you know the @file{interface.cfg} file to use, you may
957 need help from OpenOCD to discover what's on the board.
958 Once you find the JTAG TAPs, you can just search for appropriate
960 configuration files ... or write your own, from the bottom up.
961 @xref{autoprobing,,Autoprobing}.
963 @item You can often reuse some standard config files but
964 need to write a few new ones, probably a @file{board.cfg} file.
965 You will be using commands described later in this User's Guide,
966 and working with the guidelines in the next chapter.
968 For example, there may be configuration files for your JTAG adapter
969 and target chip, but you need a new board-specific config file
970 giving access to your particular flash chips.
971 Or you might need to write another target chip configuration file
972 for a new chip built around the Cortex M3 core.
975 When you write new configuration files, please submit
976 them for inclusion in the next OpenOCD release.
977 For example, a @file{board/newboard.cfg} file will help the
978 next users of that board, and a @file{target/newcpu.cfg}
979 will help support users of any board using that chip.
983 You may may need to write some C code.
984 It may be as simple as a supporting a new ft2232 or parport
985 based adapter; a bit more involved, like a NAND or NOR flash
986 controller driver; or a big piece of work like supporting
987 a new chip architecture.
990 Reuse the existing config files when you can.
991 Look first in the @file{scripts/boards} area, then @file{scripts/targets}.
992 You may find a board configuration that's a good example to follow.
994 When you write config files, separate the reusable parts
995 (things every user of that interface, chip, or board needs)
996 from ones specific to your environment and debugging approach.
1000 For example, a @code{gdb-attach} event handler that invokes
1001 the @command{reset init} command will interfere with debugging
1002 early boot code, which performs some of the same actions
1003 that the @code{reset-init} event handler does.
1006 Likewise, the @command{arm9 vector_catch} command (or
1007 @cindex vector_catch
1008 its siblings @command{xscale vector_catch}
1009 and @command{cortex_m vector_catch}) can be a timesaver
1010 during some debug sessions, but don't make everyone use that either.
1011 Keep those kinds of debugging aids in your user config file,
1012 along with messaging and tracing setup.
1013 (@xref{softwaredebugmessagesandtracing,,Software Debug Messages and Tracing}.)
1016 You might need to override some defaults.
1017 For example, you might need to move, shrink, or back up the target's
1018 work area if your application needs much SRAM.
1021 TCP/IP port configuration is another example of something which
1022 is environment-specific, and should only appear in
1023 a user config file. @xref{tcpipports,,TCP/IP Ports}.
1026 @section Project-Specific Utilities
1028 A few project-specific utility
1029 routines may well speed up your work.
1030 Write them, and keep them in your project's user config file.
1032 For example, if you are making a boot loader work on a
1033 board, it's nice to be able to debug the ``after it's
1034 loaded to RAM'' parts separately from the finicky early
1035 code which sets up the DDR RAM controller and clocks.
1036 A script like this one, or a more GDB-aware sibling,
1040 proc ramboot @{ @} @{
1041 # Reset, running the target's "reset-init" scripts
1042 # to initialize clocks and the DDR RAM controller.
1043 # Leave the CPU halted.
1046 # Load CONFIG_SKIP_LOWLEVEL_INIT version into DDR RAM.
1047 load_image u-boot.bin 0x20000000
1054 Then once that code is working you will need to make it
1055 boot from NOR flash; a different utility would help.
1056 Alternatively, some developers write to flash using GDB.
1057 (You might use a similar script if you're working with a flash
1058 based microcontroller application instead of a boot loader.)
1061 proc newboot @{ @} @{
1062 # Reset, leaving the CPU halted. The "reset-init" event
1063 # proc gives faster access to the CPU and to NOR flash;
1064 # "reset halt" would be slower.
1067 # Write standard version of U-Boot into the first two
1068 # sectors of NOR flash ... the standard version should
1069 # do the same lowlevel init as "reset-init".
1070 flash protect 0 0 1 off
1071 flash erase_sector 0 0 1
1072 flash write_bank 0 u-boot.bin 0x0
1073 flash protect 0 0 1 on
1075 # Reboot from scratch using that new boot loader.
1080 You may need more complicated utility procedures when booting
1082 That often involves an extra bootloader stage,
1083 running from on-chip SRAM to perform DDR RAM setup so it can load
1084 the main bootloader code (which won't fit into that SRAM).
1086 Other helper scripts might be used to write production system images,
1087 involving considerably more than just a three stage bootloader.
1089 @section Target Software Changes
1091 Sometimes you may want to make some small changes to the software
1092 you're developing, to help make JTAG debugging work better.
1093 For example, in C or assembly language code you might
1094 use @code{#ifdef JTAG_DEBUG} (or its converse) around code
1095 handling issues like:
1099 @item @b{Watchdog Timers}...
1100 Watchog timers are typically used to automatically reset systems if
1101 some application task doesn't periodically reset the timer. (The
1102 assumption is that the system has locked up if the task can't run.)
1103 When a JTAG debugger halts the system, that task won't be able to run
1104 and reset the timer ... potentially causing resets in the middle of
1105 your debug sessions.
1107 It's rarely a good idea to disable such watchdogs, since their usage
1108 needs to be debugged just like all other parts of your firmware.
1109 That might however be your only option.
1111 Look instead for chip-specific ways to stop the watchdog from counting
1112 while the system is in a debug halt state. It may be simplest to set
1113 that non-counting mode in your debugger startup scripts. You may however
1114 need a different approach when, for example, a motor could be physically
1115 damaged by firmware remaining inactive in a debug halt state. That might
1116 involve a type of firmware mode where that "non-counting" mode is disabled
1117 at the beginning then re-enabled at the end; a watchdog reset might fire
1118 and complicate the debug session, but hardware (or people) would be
1119 protected.@footnote{Note that many systems support a "monitor mode" debug
1120 that is a somewhat cleaner way to address such issues. You can think of
1121 it as only halting part of the system, maybe just one task,
1122 instead of the whole thing.
1123 At this writing, January 2010, OpenOCD based debugging does not support
1124 monitor mode debug, only "halt mode" debug.}
1126 @item @b{ARM Semihosting}...
1127 @cindex ARM semihosting
1128 When linked with a special runtime library provided with many
1129 toolchains@footnote{See chapter 8 "Semihosting" in
1130 @uref{http://infocenter.arm.com/help/topic/com.arm.doc.dui0203i/DUI0203I_rvct_developer_guide.pdf,
1131 ARM DUI 0203I}, the "RealView Compilation Tools Developer Guide".
1132 The CodeSourcery EABI toolchain also includes a semihosting library.},
1133 your target code can use I/O facilities on the debug host. That library
1134 provides a small set of system calls which are handled by OpenOCD.
1135 It can let the debugger provide your system console and a file system,
1136 helping with early debugging or providing a more capable environment
1137 for sometimes-complex tasks like installing system firmware onto
1140 @item @b{ARM Wait-For-Interrupt}...
1141 Many ARM chips synchronize the JTAG clock using the core clock.
1142 Low power states which stop that core clock thus prevent JTAG access.
1143 Idle loops in tasking environments often enter those low power states
1144 via the @code{WFI} instruction (or its coprocessor equivalent, before ARMv7).
1146 You may want to @emph{disable that instruction} in source code,
1147 or otherwise prevent using that state,
1148 to ensure you can get JTAG access at any time.@footnote{As a more
1149 polite alternative, some processors have special debug-oriented
1150 registers which can be used to change various features including
1151 how the low power states are clocked while debugging.
1152 The STM32 DBGMCU_CR register is an example; at the cost of extra
1153 power consumption, JTAG can be used during low power states.}
1154 For example, the OpenOCD @command{halt} command may not
1155 work for an idle processor otherwise.
1157 @item @b{Delay after reset}...
1158 Not all chips have good support for debugger access
1159 right after reset; many LPC2xxx chips have issues here.
1160 Similarly, applications that reconfigure pins used for
1161 JTAG access as they start will also block debugger access.
1163 To work with boards like this, @emph{enable a short delay loop}
1164 the first thing after reset, before "real" startup activities.
1165 For example, one second's delay is usually more than enough
1166 time for a JTAG debugger to attach, so that
1167 early code execution can be debugged
1168 or firmware can be replaced.
1170 @item @b{Debug Communications Channel (DCC)}...
1171 Some processors include mechanisms to send messages over JTAG.
1172 Many ARM cores support these, as do some cores from other vendors.
1173 (OpenOCD may be able to use this DCC internally, speeding up some
1174 operations like writing to memory.)
1176 Your application may want to deliver various debugging messages
1177 over JTAG, by @emph{linking with a small library of code}
1178 provided with OpenOCD and using the utilities there to send
1179 various kinds of message.
1180 @xref{softwaredebugmessagesandtracing,,Software Debug Messages and Tracing}.
1184 @section Target Hardware Setup
1186 Chip vendors often provide software development boards which
1187 are highly configurable, so that they can support all options
1188 that product boards may require. @emph{Make sure that any
1189 jumpers or switches match the system configuration you are
1192 Common issues include:
1196 @item @b{JTAG setup} ...
1197 Boards may support more than one JTAG configuration.
1198 Examples include jumpers controlling pullups versus pulldowns
1199 on the nTRST and/or nSRST signals, and choice of connectors
1200 (e.g. which of two headers on the base board,
1201 or one from a daughtercard).
1202 For some Texas Instruments boards, you may need to jumper the
1203 EMU0 and EMU1 signals (which OpenOCD won't currently control).
1205 @item @b{Boot Modes} ...
1206 Complex chips often support multiple boot modes, controlled
1207 by external jumpers. Make sure this is set up correctly.
1208 For example many i.MX boards from NXP need to be jumpered
1209 to "ATX mode" to start booting using the on-chip ROM, when
1210 using second stage bootloader code stored in a NAND flash chip.
1212 Such explicit configuration is common, and not limited to
1213 booting from NAND. You might also need to set jumpers to
1214 start booting using code loaded from an MMC/SD card; external
1215 SPI flash; Ethernet, UART, or USB links; NOR flash; OneNAND
1216 flash; some external host; or various other sources.
1219 @item @b{Memory Addressing} ...
1220 Boards which support multiple boot modes may also have jumpers
1221 to configure memory addressing. One board, for example, jumpers
1222 external chipselect 0 (used for booting) to address either
1223 a large SRAM (which must be pre-loaded via JTAG), NOR flash,
1224 or NAND flash. When it's jumpered to address NAND flash, that
1225 board must also be told to start booting from on-chip ROM.
1227 Your @file{board.cfg} file may also need to be told this jumper
1228 configuration, so that it can know whether to declare NOR flash
1229 using @command{flash bank} or instead declare NAND flash with
1230 @command{nand device}; and likewise which probe to perform in
1231 its @code{reset-init} handler.
1233 A closely related issue is bus width. Jumpers might need to
1234 distinguish between 8 bit or 16 bit bus access for the flash
1235 used to start booting.
1237 @item @b{Peripheral Access} ...
1238 Development boards generally provide access to every peripheral
1239 on the chip, sometimes in multiple modes (such as by providing
1240 multiple audio codec chips).
1241 This interacts with software
1242 configuration of pin multiplexing, where for example a
1243 given pin may be routed either to the MMC/SD controller
1244 or the GPIO controller. It also often interacts with
1245 configuration jumpers. One jumper may be used to route
1246 signals to an MMC/SD card slot or an expansion bus (which
1247 might in turn affect booting); others might control which
1248 audio or video codecs are used.
1252 Plus you should of course have @code{reset-init} event handlers
1253 which set up the hardware to match that jumper configuration.
1254 That includes in particular any oscillator or PLL used to clock
1255 the CPU, and any memory controllers needed to access external
1256 memory and peripherals. Without such handlers, you won't be
1257 able to access those resources without working target firmware
1258 which can do that setup ... this can be awkward when you're
1259 trying to debug that target firmware. Even if there's a ROM
1260 bootloader which handles a few issues, it rarely provides full
1261 access to all board-specific capabilities.
1264 @node Config File Guidelines
1265 @chapter Config File Guidelines
1267 This chapter is aimed at any user who needs to write a config file,
1268 including developers and integrators of OpenOCD and any user who
1269 needs to get a new board working smoothly.
1270 It provides guidelines for creating those files.
1272 You should find the following directories under @t{$(INSTALLDIR)/scripts},
1273 with files including the ones listed here.
1274 Use them as-is where you can; or as models for new files.
1276 @item @file{interface} ...
1277 These are for debug adapters.
1278 Files that configure JTAG adapters go here.
1282 altera-usb-blaster.cfg hilscher_nxhx50_re.cfg openocd-usb-hs.cfg
1283 arm-jtag-ew.cfg hitex_str9-comstick.cfg openrd.cfg
1284 at91rm9200.cfg icebear.cfg osbdm.cfg
1285 axm0432.cfg jlink.cfg parport.cfg
1286 busblaster.cfg jtagkey2.cfg parport_dlc5.cfg
1287 buspirate.cfg jtagkey2p.cfg redbee-econotag.cfg
1288 calao-usb-a9260-c01.cfg jtagkey.cfg redbee-usb.cfg
1289 calao-usb-a9260-c02.cfg jtagkey-tiny.cfg rlink.cfg
1290 calao-usb-a9260.cfg jtag-lock-pick_tiny_2.cfg sheevaplug.cfg
1291 chameleon.cfg kt-link.cfg signalyzer.cfg
1292 cortino.cfg lisa-l.cfg signalyzer-h2.cfg
1293 digilent-hs1.cfg luminary.cfg signalyzer-h4.cfg
1294 dlp-usb1232h.cfg luminary-icdi.cfg signalyzer-lite.cfg
1295 dummy.cfg luminary-lm3s811.cfg stlink-v1.cfg
1296 estick.cfg minimodule.cfg stlink-v2.cfg
1297 flashlink.cfg neodb.cfg stm32-stick.cfg
1298 flossjtag.cfg ngxtech.cfg sysfsgpio-raspberrypi.cfg
1299 flossjtag-noeeprom.cfg olimex-arm-usb-ocd.cfg ti-icdi.cfg
1300 flyswatter2.cfg olimex-arm-usb-ocd-h.cfg turtelizer2.cfg
1301 flyswatter.cfg olimex-arm-usb-tiny-h.cfg ulink.cfg
1302 ftdi olimex-jtag-tiny.cfg usb-jtag.cfg
1303 hilscher_nxhx10_etm.cfg oocdlink.cfg usbprog.cfg
1304 hilscher_nxhx500_etm.cfg opendous.cfg vpaclink.cfg
1305 hilscher_nxhx500_re.cfg opendous_ftdi.cfg vsllink.cfg
1306 hilscher_nxhx50_etm.cfg openocd-usb.cfg xds100v2.cfg
1309 axm0432.cfg icebear.cfg oocdlink.cfg
1310 calao-usb-a9260-c01.cfg jtagkey2.cfg opendous_ftdi.cfg
1311 calao-usb-a9260-c02.cfg jtagkey2p.cfg openocd-usb.cfg
1312 cortino.cfg jtagkey.cfg openocd-usb-hs.cfg
1313 dlp-usb1232h.cfg jtag-lock-pick_tiny_2.cfg openrd.cfg
1314 dp_busblaster.cfg kt-link.cfg redbee-econotag.cfg
1315 flossjtag.cfg lisa-l.cfg redbee-usb.cfg
1316 flossjtag-noeeprom.cfg luminary.cfg sheevaplug.cfg
1317 flyswatter2.cfg luminary-icdi.cfg signalyzer.cfg
1318 flyswatter.cfg luminary-lm3s811.cfg signalyzer-lite.cfg
1319 hilscher_nxhx10_etm.cfg minimodule.cfg stm32-stick.cfg
1320 hilscher_nxhx500_etm.cfg neodb.cfg turtelizer2-revB.cfg
1321 hilscher_nxhx500_re.cfg ngxtech.cfg turtelizer2-revC.cfg
1322 hilscher_nxhx50_etm.cfg olimex-arm-usb-ocd.cfg vpaclink.cfg
1323 hilscher_nxhx50_re.cfg olimex-arm-usb-ocd-h.cfg xds100v2.cfg
1324 hitex_lpc1768stick.cfg olimex-arm-usb-tiny-h.cfg
1325 hitex_str9-comstick.cfg olimex-jtag-tiny.cfg
1328 @item @file{board} ...
1329 think Circuit Board, PWA, PCB, they go by many names. Board files
1330 contain initialization items that are specific to a board.
1331 They reuse target configuration files, since the same
1332 microprocessor chips are used on many boards,
1333 but support for external parts varies widely. For
1334 example, the SDRAM initialization sequence for the board, or the type
1335 of external flash and what address it uses. Any initialization
1336 sequence to enable that external flash or SDRAM should be found in the
1337 board file. Boards may also contain multiple targets: two CPUs; or
1341 actux3.cfg lpc1850_spifi_generic.cfg
1342 am3517evm.cfg lpc4350_spifi_generic.cfg
1343 arm_evaluator7t.cfg lubbock.cfg
1344 at91cap7a-stk-sdram.cfg mcb1700.cfg
1345 at91eb40a.cfg microchip_explorer16.cfg
1346 at91rm9200-dk.cfg mini2440.cfg
1347 at91rm9200-ek.cfg mini6410.cfg
1348 at91sam9261-ek.cfg netgear-dg834v3.cfg
1349 at91sam9263-ek.cfg olimex_LPC2378STK.cfg
1350 at91sam9g20-ek.cfg olimex_lpc_h2148.cfg
1351 atmel_at91sam7s-ek.cfg olimex_sam7_ex256.cfg
1352 atmel_at91sam9260-ek.cfg olimex_sam9_l9260.cfg
1353 atmel_at91sam9rl-ek.cfg olimex_stm32_h103.cfg
1354 atmel_sam3n_ek.cfg olimex_stm32_h107.cfg
1355 atmel_sam3s_ek.cfg olimex_stm32_p107.cfg
1356 atmel_sam3u_ek.cfg omap2420_h4.cfg
1357 atmel_sam3x_ek.cfg open-bldc.cfg
1358 atmel_sam4s_ek.cfg openrd.cfg
1359 balloon3-cpu.cfg osk5912.cfg
1360 colibri.cfg phone_se_j100i.cfg
1361 crossbow_tech_imote2.cfg phytec_lpc3250.cfg
1362 csb337.cfg pic-p32mx.cfg
1363 csb732.cfg propox_mmnet1001.cfg
1364 da850evm.cfg pxa255_sst.cfg
1365 digi_connectcore_wi-9c.cfg redbee.cfg
1366 diolan_lpc4350-db1.cfg rsc-w910.cfg
1367 dm355evm.cfg sheevaplug.cfg
1368 dm365evm.cfg smdk6410.cfg
1369 dm6446evm.cfg spear300evb.cfg
1370 efikamx.cfg spear300evb_mod.cfg
1371 eir.cfg spear310evb20.cfg
1372 ek-lm3s1968.cfg spear310evb20_mod.cfg
1373 ek-lm3s3748.cfg spear320cpu.cfg
1374 ek-lm3s6965.cfg spear320cpu_mod.cfg
1375 ek-lm3s811.cfg steval_pcc010.cfg
1376 ek-lm3s811-revb.cfg stm320518_eval_stlink.cfg
1377 ek-lm3s8962.cfg stm32100b_eval.cfg
1378 ek-lm3s9b9x.cfg stm3210b_eval.cfg
1379 ek-lm3s9d92.cfg stm3210c_eval.cfg
1380 ek-lm4f120xl.cfg stm3210e_eval.cfg
1381 ek-lm4f232.cfg stm3220g_eval.cfg
1382 embedded-artists_lpc2478-32.cfg stm3220g_eval_stlink.cfg
1383 ethernut3.cfg stm3241g_eval.cfg
1384 glyn_tonga2.cfg stm3241g_eval_stlink.cfg
1385 hammer.cfg stm32f0discovery.cfg
1386 hilscher_nxdb500sys.cfg stm32f3discovery.cfg
1387 hilscher_nxeb500hmi.cfg stm32f4discovery.cfg
1388 hilscher_nxhx10.cfg stm32ldiscovery.cfg
1389 hilscher_nxhx500.cfg stm32vldiscovery.cfg
1390 hilscher_nxhx50.cfg str910-eval.cfg
1391 hilscher_nxsb100.cfg telo.cfg
1392 hitex_lpc1768stick.cfg ti_am335xevm.cfg
1393 hitex_lpc2929.cfg ti_beagleboard.cfg
1394 hitex_stm32-performancestick.cfg ti_beagleboard_xm.cfg
1395 hitex_str9-comstick.cfg ti_beaglebone.cfg
1396 iar_lpc1768.cfg ti_blaze.cfg
1397 iar_str912_sk.cfg ti_pandaboard.cfg
1398 icnova_imx53_sodimm.cfg ti_pandaboard_es.cfg
1399 icnova_sam9g45_sodimm.cfg topas910.cfg
1400 imx27ads.cfg topasa900.cfg
1401 imx27lnst.cfg twr-k60f120m.cfg
1402 imx28evk.cfg twr-k60n512.cfg
1403 imx31pdk.cfg tx25_stk5.cfg
1404 imx35pdk.cfg tx27_stk5.cfg
1405 imx53loco.cfg unknown_at91sam9260.cfg
1406 keil_mcb1700.cfg uptech_2410.cfg
1407 keil_mcb2140.cfg verdex.cfg
1408 kwikstik.cfg voipac.cfg
1409 linksys_nslu2.cfg voltcraft_dso-3062c.cfg
1410 lisa-l.cfg x300t.cfg
1411 logicpd_imx27.cfg zy1000.cfg
1414 @item @file{target} ...
1415 think chip. The ``target'' directory represents the JTAG TAPs
1417 which OpenOCD should control, not a board. Two common types of targets
1418 are ARM chips and FPGA or CPLD chips.
1419 When a chip has multiple TAPs (maybe it has both ARM and DSP cores),
1420 the target config file defines all of them.
1423 aduc702x.cfg lpc1763.cfg
1424 am335x.cfg lpc1764.cfg
1425 amdm37x.cfg lpc1765.cfg
1426 ar71xx.cfg lpc1766.cfg
1427 at32ap7000.cfg lpc1767.cfg
1428 at91r40008.cfg lpc1768.cfg
1429 at91rm9200.cfg lpc1769.cfg
1430 at91sam3ax_4x.cfg lpc1788.cfg
1431 at91sam3ax_8x.cfg lpc17xx.cfg
1432 at91sam3ax_xx.cfg lpc1850.cfg
1433 at91sam3nXX.cfg lpc2103.cfg
1434 at91sam3sXX.cfg lpc2124.cfg
1435 at91sam3u1c.cfg lpc2129.cfg
1436 at91sam3u1e.cfg lpc2148.cfg
1437 at91sam3u2c.cfg lpc2294.cfg
1438 at91sam3u2e.cfg lpc2378.cfg
1439 at91sam3u4c.cfg lpc2460.cfg
1440 at91sam3u4e.cfg lpc2478.cfg
1441 at91sam3uxx.cfg lpc2900.cfg
1442 at91sam3XXX.cfg lpc2xxx.cfg
1443 at91sam4sd32x.cfg lpc3131.cfg
1444 at91sam4sXX.cfg lpc3250.cfg
1445 at91sam4XXX.cfg lpc4350.cfg
1446 at91sam7se512.cfg lpc4350.cfg.orig
1447 at91sam7sx.cfg mc13224v.cfg
1448 at91sam7x256.cfg nuc910.cfg
1449 at91sam7x512.cfg omap2420.cfg
1450 at91sam9260.cfg omap3530.cfg
1451 at91sam9260_ext_RAM_ext_flash.cfg omap4430.cfg
1452 at91sam9261.cfg omap4460.cfg
1453 at91sam9263.cfg omap5912.cfg
1454 at91sam9.cfg omapl138.cfg
1455 at91sam9g10.cfg pic32mx.cfg
1456 at91sam9g20.cfg pxa255.cfg
1457 at91sam9g45.cfg pxa270.cfg
1458 at91sam9rl.cfg pxa3xx.cfg
1459 atmega128.cfg readme.txt
1460 avr32.cfg samsung_s3c2410.cfg
1461 c100.cfg samsung_s3c2440.cfg
1462 c100config.tcl samsung_s3c2450.cfg
1463 c100helper.tcl samsung_s3c4510.cfg
1464 c100regs.tcl samsung_s3c6410.cfg
1465 cs351x.cfg sharp_lh79532.cfg
1466 davinci.cfg smp8634.cfg
1467 dragonite.cfg spear3xx.cfg
1468 dsp56321.cfg stellaris.cfg
1469 dsp568013.cfg stellaris_icdi.cfg
1470 dsp568037.cfg stm32f0x_stlink.cfg
1471 efm32_stlink.cfg stm32f1x.cfg
1472 epc9301.cfg stm32f1x_stlink.cfg
1473 faux.cfg stm32f2x.cfg
1474 feroceon.cfg stm32f2x_stlink.cfg
1475 fm3.cfg stm32f3x.cfg
1476 hilscher_netx10.cfg stm32f3x_stlink.cfg
1477 hilscher_netx500.cfg stm32f4x.cfg
1478 hilscher_netx50.cfg stm32f4x_stlink.cfg
1479 icepick.cfg stm32l.cfg
1480 imx21.cfg stm32lx_dual_bank.cfg
1481 imx25.cfg stm32lx_stlink.cfg
1482 imx27.cfg stm32_stlink.cfg
1483 imx28.cfg stm32w108_stlink.cfg
1484 imx31.cfg stm32xl.cfg
1485 imx35.cfg str710.cfg
1486 imx51.cfg str730.cfg
1487 imx53.cfg str750.cfg
1490 is5114.cfg test_reset_syntax_error.cfg
1491 ixp42x.cfg test_syntax_error.cfg
1493 k60.cfg ti_calypso.cfg
1494 lpc1751.cfg ti_dm355.cfg
1495 lpc1752.cfg ti_dm365.cfg
1496 lpc1754.cfg ti_dm6446.cfg
1497 lpc1756.cfg tmpa900.cfg
1498 lpc1758.cfg tmpa910.cfg
1499 lpc1759.cfg u8500.cfg
1501 @item @emph{more} ... browse for other library files which may be useful.
1502 For example, there are various generic and CPU-specific utilities.
1505 The @file{openocd.cfg} user config
1506 file may override features in any of the above files by
1507 setting variables before sourcing the target file, or by adding
1508 commands specific to their situation.
1510 @section Interface Config Files
1512 The user config file
1513 should be able to source one of these files with a command like this:
1516 source [find interface/FOOBAR.cfg]
1519 A preconfigured interface file should exist for every debug adapter
1520 in use today with OpenOCD.
1521 That said, perhaps some of these config files
1522 have only been used by the developer who created it.
1524 A separate chapter gives information about how to set these up.
1525 @xref{Debug Adapter Configuration}.
1526 Read the OpenOCD source code (and Developer's Guide)
1527 if you have a new kind of hardware interface
1528 and need to provide a driver for it.
1530 @section Board Config Files
1531 @cindex config file, board
1532 @cindex board config file
1534 The user config file
1535 should be able to source one of these files with a command like this:
1538 source [find board/FOOBAR.cfg]
1541 The point of a board config file is to package everything
1542 about a given board that user config files need to know.
1543 In summary the board files should contain (if present)
1546 @item One or more @command{source [target/...cfg]} statements
1547 @item NOR flash configuration (@pxref{norconfiguration,,NOR Configuration})
1548 @item NAND flash configuration (@pxref{nandconfiguration,,NAND Configuration})
1549 @item Target @code{reset} handlers for SDRAM and I/O configuration
1550 @item JTAG adapter reset configuration (@pxref{Reset Configuration})
1551 @item All things that are not ``inside a chip''
1554 Generic things inside target chips belong in target config files,
1555 not board config files. So for example a @code{reset-init} event
1556 handler should know board-specific oscillator and PLL parameters,
1557 which it passes to target-specific utility code.
1559 The most complex task of a board config file is creating such a
1560 @code{reset-init} event handler.
1561 Define those handlers last, after you verify the rest of the board
1562 configuration works.
1564 @subsection Communication Between Config files
1566 In addition to target-specific utility code, another way that
1567 board and target config files communicate is by following a
1568 convention on how to use certain variables.
1570 The full Tcl/Tk language supports ``namespaces'', but Jim-Tcl does not.
1571 Thus the rule we follow in OpenOCD is this: Variables that begin with
1572 a leading underscore are temporary in nature, and can be modified and
1573 used at will within a target configuration file.
1575 Complex board config files can do the things like this,
1576 for a board with three chips:
1579 # Chip #1: PXA270 for network side, big endian
1580 set CHIPNAME network
1582 source [find target/pxa270.cfg]
1583 # on return: _TARGETNAME = network.cpu
1584 # other commands can refer to the "network.cpu" target.
1585 $_TARGETNAME configure .... events for this CPU..
1587 # Chip #2: PXA270 for video side, little endian
1590 source [find target/pxa270.cfg]
1591 # on return: _TARGETNAME = video.cpu
1592 # other commands can refer to the "video.cpu" target.
1593 $_TARGETNAME configure .... events for this CPU..
1595 # Chip #3: Xilinx FPGA for glue logic
1598 source [find target/spartan3.cfg]
1601 That example is oversimplified because it doesn't show any flash memory,
1602 or the @code{reset-init} event handlers to initialize external DRAM
1603 or (assuming it needs it) load a configuration into the FPGA.
1604 Such features are usually needed for low-level work with many boards,
1605 where ``low level'' implies that the board initialization software may
1606 not be working. (That's a common reason to need JTAG tools. Another
1607 is to enable working with microcontroller-based systems, which often
1608 have no debugging support except a JTAG connector.)
1610 Target config files may also export utility functions to board and user
1611 config files. Such functions should use name prefixes, to help avoid
1614 Board files could also accept input variables from user config files.
1615 For example, there might be a @code{J4_JUMPER} setting used to identify
1616 what kind of flash memory a development board is using, or how to set
1617 up other clocks and peripherals.
1619 @subsection Variable Naming Convention
1620 @cindex variable names
1622 Most boards have only one instance of a chip.
1623 However, it should be easy to create a board with more than
1624 one such chip (as shown above).
1625 Accordingly, we encourage these conventions for naming
1626 variables associated with different @file{target.cfg} files,
1627 to promote consistency and
1628 so that board files can override target defaults.
1630 Inputs to target config files include:
1633 @item @code{CHIPNAME} ...
1634 This gives a name to the overall chip, and is used as part of
1635 tap identifier dotted names.
1636 While the default is normally provided by the chip manufacturer,
1637 board files may need to distinguish between instances of a chip.
1638 @item @code{ENDIAN} ...
1639 By default @option{little} - although chips may hard-wire @option{big}.
1640 Chips that can't change endianness don't need to use this variable.
1641 @item @code{CPUTAPID} ...
1642 When OpenOCD examines the JTAG chain, it can be told verify the
1643 chips against the JTAG IDCODE register.
1644 The target file will hold one or more defaults, but sometimes the
1645 chip in a board will use a different ID (perhaps a newer revision).
1648 Outputs from target config files include:
1651 @item @code{_TARGETNAME} ...
1652 By convention, this variable is created by the target configuration
1653 script. The board configuration file may make use of this variable to
1654 configure things like a ``reset init'' script, or other things
1655 specific to that board and that target.
1656 If the chip has 2 targets, the names are @code{_TARGETNAME0},
1657 @code{_TARGETNAME1}, ... etc.
1660 @subsection The reset-init Event Handler
1661 @cindex event, reset-init
1662 @cindex reset-init handler
1664 Board config files run in the OpenOCD configuration stage;
1665 they can't use TAPs or targets, since they haven't been
1667 This means you can't write memory or access chip registers;
1668 you can't even verify that a flash chip is present.
1669 That's done later in event handlers, of which the target @code{reset-init}
1670 handler is one of the most important.
1672 Except on microcontrollers, the basic job of @code{reset-init} event
1673 handlers is setting up flash and DRAM, as normally handled by boot loaders.
1674 Microcontrollers rarely use boot loaders; they run right out of their
1675 on-chip flash and SRAM memory. But they may want to use one of these
1676 handlers too, if just for developer convenience.
1679 Because this is so very board-specific, and chip-specific, no examples
1681 Instead, look at the board config files distributed with OpenOCD.
1682 If you have a boot loader, its source code will help; so will
1683 configuration files for other JTAG tools
1684 (@pxref{translatingconfigurationfiles,,Translating Configuration Files}).
1687 Some of this code could probably be shared between different boards.
1688 For example, setting up a DRAM controller often doesn't differ by
1689 much except the bus width (16 bits or 32?) and memory timings, so a
1690 reusable TCL procedure loaded by the @file{target.cfg} file might take
1691 those as parameters.
1692 Similarly with oscillator, PLL, and clock setup;
1693 and disabling the watchdog.
1694 Structure the code cleanly, and provide comments to help
1695 the next developer doing such work.
1696 (@emph{You might be that next person} trying to reuse init code!)
1698 The last thing normally done in a @code{reset-init} handler is probing
1699 whatever flash memory was configured. For most chips that needs to be
1700 done while the associated target is halted, either because JTAG memory
1701 access uses the CPU or to prevent conflicting CPU access.
1703 @subsection JTAG Clock Rate
1705 Before your @code{reset-init} handler has set up
1706 the PLLs and clocking, you may need to run with
1707 a low JTAG clock rate.
1708 @xref{jtagspeed,,JTAG Speed}.
1709 Then you'd increase that rate after your handler has
1710 made it possible to use the faster JTAG clock.
1711 When the initial low speed is board-specific, for example
1712 because it depends on a board-specific oscillator speed, then
1713 you should probably set it up in the board config file;
1714 if it's target-specific, it belongs in the target config file.
1716 For most ARM-based processors the fastest JTAG clock@footnote{A FAQ
1717 @uref{http://www.arm.com/support/faqdev/4170.html} gives details.}
1718 is one sixth of the CPU clock; or one eighth for ARM11 cores.
1719 Consult chip documentation to determine the peak JTAG clock rate,
1720 which might be less than that.
1723 On most ARMs, JTAG clock detection is coupled to the core clock, so
1724 software using a @option{wait for interrupt} operation blocks JTAG access.
1725 Adaptive clocking provides a partial workaround, but a more complete
1726 solution just avoids using that instruction with JTAG debuggers.
1729 If both the chip and the board support adaptive clocking,
1730 use the @command{jtag_rclk}
1731 command, in case your board is used with JTAG adapter which
1732 also supports it. Otherwise use @command{adapter_khz}.
1733 Set the slow rate at the beginning of the reset sequence,
1734 and the faster rate as soon as the clocks are at full speed.
1736 @anchor{theinitboardprocedure}
1737 @subsection The init_board procedure
1738 @cindex init_board procedure
1740 The concept of @code{init_board} procedure is very similar to @code{init_targets}
1741 (@xref{theinittargetsprocedure,,The init_targets procedure}.) - it's a replacement of ``linear''
1742 configuration scripts. This procedure is meant to be executed when OpenOCD enters run stage
1743 (@xref{enteringtherunstage,,Entering the Run Stage},) after @code{init_targets}. The idea to have
1744 spearate @code{init_targets} and @code{init_board} procedures is to allow the first one to configure
1745 everything target specific (internal flash, internal RAM, etc.) and the second one to configure
1746 everything board specific (reset signals, chip frequency, reset-init event handler, external memory, etc.).
1747 Additionally ``linear'' board config file will most likely fail when target config file uses
1748 @code{init_targets} scheme (``linear'' script is executed before @code{init} and @code{init_targets} - after),
1749 so separating these two configuration stages is very convenient, as the easiest way to overcome this
1750 problem is to convert board config file to use @code{init_board} procedure. Board config scripts don't
1751 need to override @code{init_targets} defined in target config files when they only need to to add some specifics.
1753 Just as @code{init_targets}, the @code{init_board} procedure can be overriden by ``next level'' script (which sources
1754 the original), allowing greater code reuse.
1757 ### board_file.cfg ###
1759 # source target file that does most of the config in init_targets
1760 source [find target/target.cfg]
1762 proc enable_fast_clock @{@} @{
1763 # enables fast on-board clock source
1764 # configures the chip to use it
1767 # initialize only board specifics - reset, clock, adapter frequency
1768 proc init_board @{@} @{
1769 reset_config trst_and_srst trst_pulls_srst
1771 $_TARGETNAME configure -event reset-init @{
1779 @section Target Config Files
1780 @cindex config file, target
1781 @cindex target config file
1783 Board config files communicate with target config files using
1784 naming conventions as described above, and may source one or
1785 more target config files like this:
1788 source [find target/FOOBAR.cfg]
1791 The point of a target config file is to package everything
1792 about a given chip that board config files need to know.
1793 In summary the target files should contain
1797 @item Add TAPs to the scan chain
1798 @item Add CPU targets (includes GDB support)
1799 @item CPU/Chip/CPU-Core specific features
1803 As a rule of thumb, a target file sets up only one chip.
1804 For a microcontroller, that will often include a single TAP,
1805 which is a CPU needing a GDB target, and its on-chip flash.
1807 More complex chips may include multiple TAPs, and the target
1808 config file may need to define them all before OpenOCD
1809 can talk to the chip.
1810 For example, some phone chips have JTAG scan chains that include
1811 an ARM core for operating system use, a DSP,
1812 another ARM core embedded in an image processing engine,
1813 and other processing engines.
1815 @subsection Default Value Boiler Plate Code
1817 All target configuration files should start with code like this,
1818 letting board config files express environment-specific
1819 differences in how things should be set up.
1822 # Boards may override chip names, perhaps based on role,
1823 # but the default should match what the vendor uses
1824 if @{ [info exists CHIPNAME] @} @{
1825 set _CHIPNAME $CHIPNAME
1827 set _CHIPNAME sam7x256
1830 # ONLY use ENDIAN with targets that can change it.
1831 if @{ [info exists ENDIAN] @} @{
1837 # TAP identifiers may change as chips mature, for example with
1838 # new revision fields (the "3" here). Pick a good default; you
1839 # can pass several such identifiers to the "jtag newtap" command.
1840 if @{ [info exists CPUTAPID ] @} @{
1841 set _CPUTAPID $CPUTAPID
1843 set _CPUTAPID 0x3f0f0f0f
1846 @c but 0x3f0f0f0f is for an str73x part ...
1848 @emph{Remember:} Board config files may include multiple target
1849 config files, or the same target file multiple times
1850 (changing at least @code{CHIPNAME}).
1852 Likewise, the target configuration file should define
1853 @code{_TARGETNAME} (or @code{_TARGETNAME0} etc) and
1854 use it later on when defining debug targets:
1857 set _TARGETNAME $_CHIPNAME.cpu
1858 target create $_TARGETNAME arm7tdmi -chain-position $_TARGETNAME
1861 @subsection Adding TAPs to the Scan Chain
1862 After the ``defaults'' are set up,
1863 add the TAPs on each chip to the JTAG scan chain.
1864 @xref{TAP Declaration}, and the naming convention
1867 In the simplest case the chip has only one TAP,
1868 probably for a CPU or FPGA.
1869 The config file for the Atmel AT91SAM7X256
1870 looks (in part) like this:
1873 jtag newtap $_CHIPNAME cpu -irlen 4 -expected-id $_CPUTAPID
1876 A board with two such at91sam7 chips would be able
1877 to source such a config file twice, with different
1878 values for @code{CHIPNAME}, so
1879 it adds a different TAP each time.
1881 If there are nonzero @option{-expected-id} values,
1882 OpenOCD attempts to verify the actual tap id against those values.
1883 It will issue error messages if there is mismatch, which
1884 can help to pinpoint problems in OpenOCD configurations.
1887 JTAG tap: sam7x256.cpu tap/device found: 0x3f0f0f0f
1888 (Manufacturer: 0x787, Part: 0xf0f0, Version: 0x3)
1889 ERROR: Tap: sam7x256.cpu - Expected id: 0x12345678, Got: 0x3f0f0f0f
1890 ERROR: expected: mfg: 0x33c, part: 0x2345, ver: 0x1
1891 ERROR: got: mfg: 0x787, part: 0xf0f0, ver: 0x3
1894 There are more complex examples too, with chips that have
1895 multiple TAPs. Ones worth looking at include:
1898 @item @file{target/omap3530.cfg} -- with disabled ARM and DSP,
1899 plus a JRC to enable them
1900 @item @file{target/str912.cfg} -- with flash, CPU, and boundary scan
1901 @item @file{target/ti_dm355.cfg} -- with ETM, ARM, and JRC (this JRC
1902 is not currently used)
1905 @subsection Add CPU targets
1907 After adding a TAP for a CPU, you should set it up so that
1908 GDB and other commands can use it.
1909 @xref{CPU Configuration}.
1910 For the at91sam7 example above, the command can look like this;
1911 note that @code{$_ENDIAN} is not needed, since OpenOCD defaults
1912 to little endian, and this chip doesn't support changing that.
1915 set _TARGETNAME $_CHIPNAME.cpu
1916 target create $_TARGETNAME arm7tdmi -chain-position $_TARGETNAME
1919 Work areas are small RAM areas associated with CPU targets.
1920 They are used by OpenOCD to speed up downloads,
1921 and to download small snippets of code to program flash chips.
1922 If the chip includes a form of ``on-chip-ram'' - and many do - define
1923 a work area if you can.
1924 Again using the at91sam7 as an example, this can look like:
1927 $_TARGETNAME configure -work-area-phys 0x00200000 \
1928 -work-area-size 0x4000 -work-area-backup 0
1931 @anchor{definecputargetsworkinginsmp}
1932 @subsection Define CPU targets working in SMP
1934 After setting targets, you can define a list of targets working in SMP.
1937 set _TARGETNAME_1 $_CHIPNAME.cpu1
1938 set _TARGETNAME_2 $_CHIPNAME.cpu2
1939 target create $_TARGETNAME_1 cortex_a -chain-position $_CHIPNAME.dap \
1940 -coreid 0 -dbgbase $_DAP_DBG1
1941 target create $_TARGETNAME_2 cortex_a -chain-position $_CHIPNAME.dap \
1942 -coreid 1 -dbgbase $_DAP_DBG2
1943 #define 2 targets working in smp.
1944 target smp $_CHIPNAME.cpu2 $_CHIPNAME.cpu1
1946 In the above example on cortex_a, 2 cpus are working in SMP.
1947 In SMP only one GDB instance is created and :
1949 @item a set of hardware breakpoint sets the same breakpoint on all targets in the list.
1950 @item halt command triggers the halt of all targets in the list.
1951 @item resume command triggers the write context and the restart of all targets in the list.
1952 @item following a breakpoint: the target stopped by the breakpoint is displayed to the GDB session.
1953 @item dedicated GDB serial protocol packets are implemented for switching/retrieving the target
1954 displayed by the GDB session @pxref{usingopenocdsmpwithgdb,,Using OpenOCD SMP with GDB}.
1957 The SMP behaviour can be disabled/enabled dynamically. On cortex_a following
1958 command have been implemented.
1960 @item cortex_a smp_on : enable SMP mode, behaviour is as described above.
1961 @item cortex_a smp_off : disable SMP mode, the current target is the one
1962 displayed in the GDB session, only this target is now controlled by GDB
1963 session. This behaviour is useful during system boot up.
1964 @item cortex_a smp_gdb : display/fix the core id displayed in GDB session see
1971 #0 : coreid 0 is displayed to GDB ,
1972 #-> -1 : next resume triggers a real resume
1973 > cortex_a smp_gdb 1
1975 #0 :coreid 0 is displayed to GDB ,
1976 #->1 : next resume displays coreid 1 to GDB
1980 #1 :coreid 1 is displayed to GDB ,
1981 #->1 : next resume displays coreid 1 to GDB
1982 > cortex_a smp_gdb -1
1984 #1 :coreid 1 is displayed to GDB,
1985 #->-1 : next resume triggers a real resume
1989 @subsection Chip Reset Setup
1991 As a rule, you should put the @command{reset_config} command
1992 into the board file. Most things you think you know about a
1993 chip can be tweaked by the board.
1995 Some chips have specific ways the TRST and SRST signals are
1996 managed. In the unusual case that these are @emph{chip specific}
1997 and can never be changed by board wiring, they could go here.
1998 For example, some chips can't support JTAG debugging without
2001 Provide a @code{reset-assert} event handler if you can.
2002 Such a handler uses JTAG operations to reset the target,
2003 letting this target config be used in systems which don't
2004 provide the optional SRST signal, or on systems where you
2005 don't want to reset all targets at once.
2006 Such a handler might write to chip registers to force a reset,
2007 use a JRC to do that (preferable -- the target may be wedged!),
2008 or force a watchdog timer to trigger.
2009 (For Cortex-M targets, this is not necessary. The target
2010 driver knows how to use trigger an NVIC reset when SRST is
2013 Some chips need special attention during reset handling if
2014 they're going to be used with JTAG.
2015 An example might be needing to send some commands right
2016 after the target's TAP has been reset, providing a
2017 @code{reset-deassert-post} event handler that writes a chip
2018 register to report that JTAG debugging is being done.
2019 Another would be reconfiguring the watchdog so that it stops
2020 counting while the core is halted in the debugger.
2022 JTAG clocking constraints often change during reset, and in
2023 some cases target config files (rather than board config files)
2024 are the right places to handle some of those issues.
2025 For example, immediately after reset most chips run using a
2026 slower clock than they will use later.
2027 That means that after reset (and potentially, as OpenOCD
2028 first starts up) they must use a slower JTAG clock rate
2029 than they will use later.
2030 @xref{jtagspeed,,JTAG Speed}.
2032 @quotation Important
2033 When you are debugging code that runs right after chip
2034 reset, getting these issues right is critical.
2035 In particular, if you see intermittent failures when
2036 OpenOCD verifies the scan chain after reset,
2037 look at how you are setting up JTAG clocking.
2040 @anchor{theinittargetsprocedure}
2041 @subsection The init_targets procedure
2042 @cindex init_targets procedure
2044 Target config files can either be ``linear'' (script executed line-by-line when parsed in
2045 configuration stage, @xref{configurationstage,,Configuration Stage},) or they can contain a special
2046 procedure called @code{init_targets}, which will be executed when entering run stage
2047 (after parsing all config files or after @code{init} command, @xref{enteringtherunstage,,Entering the Run Stage}.)
2048 Such procedure can be overriden by ``next level'' script (which sources the original).
2049 This concept faciliates code reuse when basic target config files provide generic configuration
2050 procedures and @code{init_targets} procedure, which can then be sourced and enchanced or changed in
2051 a ``more specific'' target config file. This is not possible with ``linear'' config scripts,
2052 because sourcing them executes every initialization commands they provide.
2055 ### generic_file.cfg ###
2057 proc setup_my_chip @{chip_name flash_size ram_size@} @{
2058 # basic initialization procedure ...
2061 proc init_targets @{@} @{
2062 # initializes generic chip with 4kB of flash and 1kB of RAM
2063 setup_my_chip MY_GENERIC_CHIP 4096 1024
2066 ### specific_file.cfg ###
2068 source [find target/generic_file.cfg]
2070 proc init_targets @{@} @{
2071 # initializes specific chip with 128kB of flash and 64kB of RAM
2072 setup_my_chip MY_CHIP_WITH_128K_FLASH_64KB_RAM 131072 65536
2076 The easiest way to convert ``linear'' config files to @code{init_targets} version is to
2077 enclose every line of ``code'' (i.e. not @code{source} commands, procedures, etc.) in this procedure.
2079 For an example of this scheme see LPC2000 target config files.
2081 The @code{init_boards} procedure is a similar concept concerning board config files
2082 (@xref{theinitboardprocedure,,The init_board procedure}.)
2084 @subsection ARM Core Specific Hacks
2086 If the chip has a DCC, enable it. If the chip is an ARM9 with some
2087 special high speed download features - enable it.
2089 If present, the MMU, the MPU and the CACHE should be disabled.
2091 Some ARM cores are equipped with trace support, which permits
2092 examination of the instruction and data bus activity. Trace
2093 activity is controlled through an ``Embedded Trace Module'' (ETM)
2094 on one of the core's scan chains. The ETM emits voluminous data
2095 through a ``trace port''. (@xref{armhardwaretracing,,ARM Hardware Tracing}.)
2096 If you are using an external trace port,
2097 configure it in your board config file.
2098 If you are using an on-chip ``Embedded Trace Buffer'' (ETB),
2099 configure it in your target config file.
2102 etm config $_TARGETNAME 16 normal full etb
2103 etb config $_TARGETNAME $_CHIPNAME.etb
2106 @subsection Internal Flash Configuration
2108 This applies @b{ONLY TO MICROCONTROLLERS} that have flash built in.
2110 @b{Never ever} in the ``target configuration file'' define any type of
2111 flash that is external to the chip. (For example a BOOT flash on
2112 Chip Select 0.) Such flash information goes in a board file - not
2113 the TARGET (chip) file.
2117 @item at91sam7x256 - has 256K flash YES enable it.
2118 @item str912 - has flash internal YES enable it.
2119 @item imx27 - uses boot flash on CS0 - it goes in the board file.
2120 @item pxa270 - again - CS0 flash - it goes in the board file.
2123 @anchor{translatingconfigurationfiles}
2124 @section Translating Configuration Files
2126 If you have a configuration file for another hardware debugger
2127 or toolset (Abatron, BDI2000, BDI3000, CCS,
2128 Lauterbach, Segger, Macraigor, etc.), translating
2129 it into OpenOCD syntax is often quite straightforward. The most tricky
2130 part of creating a configuration script is oftentimes the reset init
2131 sequence where e.g. PLLs, DRAM and the like is set up.
2133 One trick that you can use when translating is to write small
2134 Tcl procedures to translate the syntax into OpenOCD syntax. This
2135 can avoid manual translation errors and make it easier to
2136 convert other scripts later on.
2138 Example of transforming quirky arguments to a simple search and
2142 # Lauterbach syntax(?)
2144 # Data.Set c15:0x042f %long 0x40000015
2146 # OpenOCD syntax when using procedure below.
2148 # setc15 0x01 0x00050078
2150 proc setc15 @{regs value@} @{
2153 echo [format "set p15 0x%04x, 0x%08x" $regs $value]
2155 arm mcr 15 [expr ($regs>>12)&0x7] \
2156 [expr ($regs>>0)&0xf] [expr ($regs>>4)&0xf] \
2157 [expr ($regs>>8)&0x7] $value
2163 @node Daemon Configuration
2164 @chapter Daemon Configuration
2165 @cindex initialization
2166 The commands here are commonly found in the openocd.cfg file and are
2167 used to specify what TCP/IP ports are used, and how GDB should be
2170 @anchor{configurationstage}
2171 @section Configuration Stage
2172 @cindex configuration stage
2173 @cindex config command
2175 When the OpenOCD server process starts up, it enters a
2176 @emph{configuration stage} which is the only time that
2177 certain commands, @emph{configuration commands}, may be issued.
2178 Normally, configuration commands are only available
2179 inside startup scripts.
2181 In this manual, the definition of a configuration command is
2182 presented as a @emph{Config Command}, not as a @emph{Command}
2183 which may be issued interactively.
2184 The runtime @command{help} command also highlights configuration
2185 commands, and those which may be issued at any time.
2187 Those configuration commands include declaration of TAPs,
2189 the interface used for JTAG communication,
2190 and other basic setup.
2191 The server must leave the configuration stage before it
2192 may access or activate TAPs.
2193 After it leaves this stage, configuration commands may no
2196 @anchor{enteringtherunstage}
2197 @section Entering the Run Stage
2199 The first thing OpenOCD does after leaving the configuration
2200 stage is to verify that it can talk to the scan chain
2201 (list of TAPs) which has been configured.
2202 It will warn if it doesn't find TAPs it expects to find,
2203 or finds TAPs that aren't supposed to be there.
2204 You should see no errors at this point.
2205 If you see errors, resolve them by correcting the
2206 commands you used to configure the server.
2207 Common errors include using an initial JTAG speed that's too
2208 fast, and not providing the right IDCODE values for the TAPs
2211 Once OpenOCD has entered the run stage, a number of commands
2213 A number of these relate to the debug targets you may have declared.
2214 For example, the @command{mww} command will not be available until
2215 a target has been successfuly instantiated.
2216 If you want to use those commands, you may need to force
2217 entry to the run stage.
2219 @deffn {Config Command} init
2220 This command terminates the configuration stage and
2221 enters the run stage. This helps when you need to have
2222 the startup scripts manage tasks such as resetting the target,
2223 programming flash, etc. To reset the CPU upon startup, add "init" and
2224 "reset" at the end of the config script or at the end of the OpenOCD
2225 command line using the @option{-c} command line switch.
2227 If this command does not appear in any startup/configuration file
2228 OpenOCD executes the command for you after processing all
2229 configuration files and/or command line options.
2231 @b{NOTE:} This command normally occurs at or near the end of your
2232 openocd.cfg file to force OpenOCD to ``initialize'' and make the
2233 targets ready. For example: If your openocd.cfg file needs to
2234 read/write memory on your target, @command{init} must occur before
2235 the memory read/write commands. This includes @command{nand probe}.
2238 @deffn {Overridable Procedure} jtag_init
2239 This is invoked at server startup to verify that it can talk
2240 to the scan chain (list of TAPs) which has been configured.
2242 The default implementation first tries @command{jtag arp_init},
2243 which uses only a lightweight JTAG reset before examining the
2245 If that fails, it tries again, using a harder reset
2246 from the overridable procedure @command{init_reset}.
2248 Implementations must have verified the JTAG scan chain before
2250 This is done by calling @command{jtag arp_init}
2251 (or @command{jtag arp_init-reset}).
2255 @section TCP/IP Ports
2260 The OpenOCD server accepts remote commands in several syntaxes.
2261 Each syntax uses a different TCP/IP port, which you may specify
2262 only during configuration (before those ports are opened).
2264 For reasons including security, you may wish to prevent remote
2265 access using one or more of these ports.
2266 In such cases, just specify the relevant port number as zero.
2267 If you disable all access through TCP/IP, you will need to
2268 use the command line @option{-pipe} option.
2270 @deffn {Command} gdb_port [number]
2272 Normally gdb listens to a TCP/IP port, but GDB can also
2273 communicate via pipes(stdin/out or named pipes). The name
2274 "gdb_port" stuck because it covers probably more than 90% of
2275 the normal use cases.
2277 No arguments reports GDB port. "pipe" means listen to stdin
2278 output to stdout, an integer is base port number, "disable"
2279 disables the gdb server.
2281 When using "pipe", also use log_output to redirect the log
2282 output to a file so as not to flood the stdin/out pipes.
2284 The -p/--pipe option is deprecated and a warning is printed
2285 as it is equivalent to passing in -c "gdb_port pipe; log_output openocd.log".
2287 Any other string is interpreted as named pipe to listen to.
2288 Output pipe is the same name as input pipe, but with 'o' appended,
2289 e.g. /var/gdb, /var/gdbo.
2291 The GDB port for the first target will be the base port, the
2292 second target will listen on gdb_port + 1, and so on.
2293 When not specified during the configuration stage,
2294 the port @var{number} defaults to 3333.
2297 @deffn {Command} tcl_port [number]
2298 Specify or query the port used for a simplified RPC
2299 connection that can be used by clients to issue TCL commands and get the
2300 output from the Tcl engine.
2301 Intended as a machine interface.
2302 When not specified during the configuration stage,
2303 the port @var{number} defaults to 6666.
2307 @deffn {Command} telnet_port [number]
2308 Specify or query the
2309 port on which to listen for incoming telnet connections.
2310 This port is intended for interaction with one human through TCL commands.
2311 When not specified during the configuration stage,
2312 the port @var{number} defaults to 4444.
2313 When specified as zero, this port is not activated.
2316 @anchor{gdbconfiguration}
2317 @section GDB Configuration
2319 @cindex GDB configuration
2320 You can reconfigure some GDB behaviors if needed.
2321 The ones listed here are static and global.
2322 @xref{targetconfiguration,,Target Configuration}, about configuring individual targets.
2323 @xref{targetevents,,Target Events}, about configuring target-specific event handling.
2325 @anchor{gdbbreakpointoverride}
2326 @deffn {Command} gdb_breakpoint_override [@option{hard}|@option{soft}|@option{disable}]
2327 Force breakpoint type for gdb @command{break} commands.
2328 This option supports GDB GUIs which don't
2329 distinguish hard versus soft breakpoints, if the default OpenOCD and
2330 GDB behaviour is not sufficient. GDB normally uses hardware
2331 breakpoints if the memory map has been set up for flash regions.
2334 @anchor{gdbflashprogram}
2335 @deffn {Config Command} gdb_flash_program (@option{enable}|@option{disable})
2336 Set to @option{enable} to cause OpenOCD to program the flash memory when a
2337 vFlash packet is received.
2338 The default behaviour is @option{enable}.
2341 @deffn {Config Command} gdb_memory_map (@option{enable}|@option{disable})
2342 Set to @option{enable} to cause OpenOCD to send the memory configuration to GDB when
2343 requested. GDB will then know when to set hardware breakpoints, and program flash
2344 using the GDB load command. @command{gdb_flash_program enable} must also be enabled
2345 for flash programming to work.
2346 Default behaviour is @option{enable}.
2347 @xref{gdbflashprogram,,gdb_flash_program}.
2350 @deffn {Config Command} gdb_report_data_abort (@option{enable}|@option{disable})
2351 Specifies whether data aborts cause an error to be reported
2352 by GDB memory read packets.
2353 The default behaviour is @option{disable};
2354 use @option{enable} see these errors reported.
2357 @anchor{eventpolling}
2358 @section Event Polling
2360 Hardware debuggers are parts of asynchronous systems,
2361 where significant events can happen at any time.
2362 The OpenOCD server needs to detect some of these events,
2363 so it can report them to through TCL command line
2366 Examples of such events include:
2369 @item One of the targets can stop running ... maybe it triggers
2370 a code breakpoint or data watchpoint, or halts itself.
2371 @item Messages may be sent over ``debug message'' channels ... many
2372 targets support such messages sent over JTAG,
2373 for receipt by the person debugging or tools.
2374 @item Loss of power ... some adapters can detect these events.
2375 @item Resets not issued through JTAG ... such reset sources
2376 can include button presses or other system hardware, sometimes
2377 including the target itself (perhaps through a watchdog).
2378 @item Debug instrumentation sometimes supports event triggering
2379 such as ``trace buffer full'' (so it can quickly be emptied)
2380 or other signals (to correlate with code behavior).
2383 None of those events are signaled through standard JTAG signals.
2384 However, most conventions for JTAG connectors include voltage
2385 level and system reset (SRST) signal detection.
2386 Some connectors also include instrumentation signals, which
2387 can imply events when those signals are inputs.
2389 In general, OpenOCD needs to periodically check for those events,
2390 either by looking at the status of signals on the JTAG connector
2391 or by sending synchronous ``tell me your status'' JTAG requests
2392 to the various active targets.
2393 There is a command to manage and monitor that polling,
2394 which is normally done in the background.
2396 @deffn Command poll [@option{on}|@option{off}]
2397 Poll the current target for its current state.
2398 (Also, @pxref{targetcurstate,,target curstate}.)
2399 If that target is in debug mode, architecture
2400 specific information about the current state is printed.
2401 An optional parameter
2402 allows background polling to be enabled and disabled.
2404 You could use this from the TCL command shell, or
2405 from GDB using @command{monitor poll} command.
2406 Leave background polling enabled while you're using GDB.
2409 background polling: on
2410 target state: halted
2411 target halted in ARM state due to debug-request, \
2412 current mode: Supervisor
2413 cpsr: 0x800000d3 pc: 0x11081bfc
2414 MMU: disabled, D-Cache: disabled, I-Cache: enabled
2419 @node Debug Adapter Configuration
2420 @chapter Debug Adapter Configuration
2421 @cindex config file, interface
2422 @cindex interface config file
2424 Correctly installing OpenOCD includes making your operating system give
2425 OpenOCD access to debug adapters. Once that has been done, Tcl commands
2426 are used to select which one is used, and to configure how it is used.
2429 Because OpenOCD started out with a focus purely on JTAG, you may find
2430 places where it wrongly presumes JTAG is the only transport protocol
2431 in use. Be aware that recent versions of OpenOCD are removing that
2432 limitation. JTAG remains more functional than most other transports.
2433 Other transports do not support boundary scan operations, or may be
2434 specific to a given chip vendor. Some might be usable only for
2435 programming flash memory, instead of also for debugging.
2438 Debug Adapters/Interfaces/Dongles are normally configured
2439 through commands in an interface configuration
2440 file which is sourced by your @file{openocd.cfg} file, or
2441 through a command line @option{-f interface/....cfg} option.
2444 source [find interface/olimex-jtag-tiny.cfg]
2448 OpenOCD what type of JTAG adapter you have, and how to talk to it.
2449 A few cases are so simple that you only need to say what driver to use:
2456 Most adapters need a bit more configuration than that.
2459 @section Interface Configuration
2461 The interface command tells OpenOCD what type of debug adapter you are
2462 using. Depending on the type of adapter, you may need to use one or
2463 more additional commands to further identify or configure the adapter.
2465 @deffn {Config Command} {interface} name
2466 Use the interface driver @var{name} to connect to the
2470 @deffn Command {interface_list}
2471 List the debug adapter drivers that have been built into
2472 the running copy of OpenOCD.
2474 @deffn Command {interface transports} transport_name+
2475 Specifies the transports supported by this debug adapter.
2476 The adapter driver builds-in similar knowledge; use this only
2477 when external configuration (such as jumpering) changes what
2478 the hardware can support.
2483 @deffn Command {adapter_name}
2484 Returns the name of the debug adapter driver being used.
2487 @section Interface Drivers
2489 Each of the interface drivers listed here must be explicitly
2490 enabled when OpenOCD is configured, in order to be made
2491 available at run time.
2493 @deffn {Interface Driver} {amt_jtagaccel}
2494 Amontec Chameleon in its JTAG Accelerator configuration,
2495 connected to a PC's EPP mode parallel port.
2496 This defines some driver-specific commands:
2498 @deffn {Config Command} {parport_port} number
2499 Specifies either the address of the I/O port (default: 0x378 for LPT1) or
2500 the number of the @file{/dev/parport} device.
2503 @deffn {Config Command} rtck [@option{enable}|@option{disable}]
2504 Displays status of RTCK option.
2505 Optionally sets that option first.
2509 @deffn {Interface Driver} {arm-jtag-ew}
2510 Olimex ARM-JTAG-EW USB adapter
2511 This has one driver-specific command:
2513 @deffn Command {armjtagew_info}
2518 @deffn {Interface Driver} {at91rm9200}
2519 Supports bitbanged JTAG from the local system,
2520 presuming that system is an Atmel AT91rm9200
2521 and a specific set of GPIOs is used.
2522 @c command: at91rm9200_device NAME
2523 @c chooses among list of bit configs ... only one option
2526 @deffn {Interface Driver} {dummy}
2527 A dummy software-only driver for debugging.
2530 @deffn {Interface Driver} {ep93xx}
2531 Cirrus Logic EP93xx based single-board computer bit-banging (in development)
2534 @deffn {Interface Driver} {ft2232}
2535 FTDI FT2232 (USB) based devices over one of the userspace libraries.
2537 Note that this driver has several flaws and the @command{ftdi} driver is
2538 recommended as its replacement.
2540 These interfaces have several commands, used to configure the driver
2541 before initializing the JTAG scan chain:
2543 @deffn {Config Command} {ft2232_device_desc} description
2544 Provides the USB device description (the @emph{iProduct string})
2545 of the FTDI FT2232 device. If not
2546 specified, the FTDI default value is used. This setting is only valid
2547 if compiled with FTD2XX support.
2550 @deffn {Config Command} {ft2232_serial} serial-number
2551 Specifies the @var{serial-number} of the FTDI FT2232 device to use,
2552 in case the vendor provides unique IDs and more than one FT2232 device
2553 is connected to the host.
2554 If not specified, serial numbers are not considered.
2555 (Note that USB serial numbers can be arbitrary Unicode strings,
2556 and are not restricted to containing only decimal digits.)
2559 @deffn {Config Command} {ft2232_layout} name
2560 Each vendor's FT2232 device can use different GPIO signals
2561 to control output-enables, reset signals, and LEDs.
2562 Currently valid layout @var{name} values include:
2564 @item @b{axm0432_jtag} Axiom AXM-0432
2565 @item @b{comstick} Hitex STR9 comstick
2566 @item @b{cortino} Hitex Cortino JTAG interface
2567 @item @b{evb_lm3s811} TI/Luminary Micro EVB_LM3S811 as a JTAG interface,
2568 either for the local Cortex-M3 (SRST only)
2569 or in a passthrough mode (neither SRST nor TRST)
2570 This layout can not support the SWO trace mechanism, and should be
2571 used only for older boards (before rev C).
2572 @item @b{luminary_icdi} This layout should be used with most TI/Luminary
2573 eval boards, including Rev C LM3S811 eval boards and the eponymous
2574 ICDI boards, to debug either the local Cortex-M3 or in passthrough mode
2575 to debug some other target. It can support the SWO trace mechanism.
2576 @item @b{flyswatter} Tin Can Tools Flyswatter
2577 @item @b{icebear} ICEbear JTAG adapter from Section 5
2578 @item @b{jtagkey} Amontec JTAGkey and JTAGkey-Tiny (and compatibles)
2579 @item @b{jtagkey2} Amontec JTAGkey2 (and compatibles)
2580 @item @b{m5960} American Microsystems M5960
2581 @item @b{olimex-jtag} Olimex ARM-USB-OCD and ARM-USB-Tiny
2582 @item @b{oocdlink} OOCDLink
2583 @c oocdlink ~= jtagkey_prototype_v1
2584 @item @b{redbee-econotag} Integrated with a Redbee development board.
2585 @item @b{redbee-usb} Integrated with a Redbee USB-stick development board.
2586 @item @b{sheevaplug} Marvell Sheevaplug development kit
2587 @item @b{signalyzer} Xverve Signalyzer
2588 @item @b{stm32stick} Hitex STM32 Performance Stick
2589 @item @b{turtelizer2} egnite Software turtelizer2
2590 @item @b{usbjtag} "USBJTAG-1" layout described in the OpenOCD diploma thesis
2594 @deffn {Config Command} {ft2232_vid_pid} [vid pid]+
2595 The vendor ID and product ID of the FTDI FT2232 device. If not specified, the FTDI
2596 default values are used.
2597 Currently, up to eight [@var{vid}, @var{pid}] pairs may be given, e.g.
2599 ft2232_vid_pid 0x0403 0xcff8 0x15ba 0x0003
2603 @deffn {Config Command} {ft2232_latency} ms
2604 On some systems using FT2232 based JTAG interfaces the FT_Read function call in
2605 ft2232_read() fails to return the expected number of bytes. This can be caused by
2606 USB communication delays and has proved hard to reproduce and debug. Setting the
2607 FT2232 latency timer to a larger value increases delays for short USB packets but it
2608 also reduces the risk of timeouts before receiving the expected number of bytes.
2609 The OpenOCD default value is 2 and for some systems a value of 10 has proved useful.
2612 @deffn {Config Command} {ft2232_channel} channel
2613 Used to select the channel of the ft2232 chip to use (between 1 and 4).
2614 The default value is 1.
2617 For example, the interface config file for a
2618 Turtelizer JTAG Adapter looks something like this:
2622 ft2232_device_desc "Turtelizer JTAG/RS232 Adapter"
2623 ft2232_layout turtelizer2
2624 ft2232_vid_pid 0x0403 0xbdc8
2628 @deffn {Interface Driver} {ftdi}
2629 This driver is for adapters using the MPSSE (Multi-Protocol Synchronous Serial
2630 Engine) mode built into many FTDI chips, such as the FT2232, FT4232 and FT232H.
2631 It is a complete rewrite to address a large number of problems with the ft2232
2634 The driver is using libusb-1.0 in asynchronous mode to talk to the FTDI device,
2635 bypassing intermediate libraries like libftdi of D2XX. Performance-wise it is
2636 consistently faster than the ft2232 driver, sometimes several times faster.
2638 A major improvement of this driver is that support for new FTDI based adapters
2639 can be added competely through configuration files, without the need to patch
2640 and rebuild OpenOCD.
2642 The driver uses a signal abstraction to enable Tcl configuration files to
2643 define outputs for one or several FTDI GPIO. These outputs can then be
2644 controlled using the @command{ftdi_set_signal} command. Special signal names
2645 are reserved for nTRST, nSRST and LED (for blink) so that they, if defined,
2646 will be used for their customary purpose.
2648 Depending on the type of buffer attached to the FTDI GPIO, the outputs have to
2649 be controlled differently. In order to support tristateable signals such as
2650 nSRST, both a data GPIO and an output-enable GPIO can be specified for each
2651 signal. The following output buffer configurations are supported:
2654 @item Push-pull with one FTDI output as (non-)inverted data line
2655 @item Open drain with one FTDI output as (non-)inverted output-enable
2656 @item Tristate with one FTDI output as (non-)inverted data line and another
2657 FTDI output as (non-)inverted output-enable
2658 @item Unbuffered, using the FTDI GPIO as a tristate output directly by
2659 switching data and direction as necessary
2662 These interfaces have several commands, used to configure the driver
2663 before initializing the JTAG scan chain:
2665 @deffn {Config Command} {ftdi_vid_pid} [vid pid]+
2666 The vendor ID and product ID of the adapter. If not specified, the FTDI
2667 default values are used.
2668 Currently, up to eight [@var{vid}, @var{pid}] pairs may be given, e.g.
2670 ftdi_vid_pid 0x0403 0xcff8 0x15ba 0x0003
2674 @deffn {Config Command} {ftdi_device_desc} description
2675 Provides the USB device description (the @emph{iProduct string})
2676 of the adapter. If not specified, the device description is ignored
2677 during device selection.
2680 @deffn {Config Command} {ftdi_serial} serial-number
2681 Specifies the @var{serial-number} of the adapter to use,
2682 in case the vendor provides unique IDs and more than one adapter
2683 is connected to the host.
2684 If not specified, serial numbers are not considered.
2685 (Note that USB serial numbers can be arbitrary Unicode strings,
2686 and are not restricted to containing only decimal digits.)
2689 @deffn {Config Command} {ftdi_channel} channel
2690 Selects the channel of the FTDI device to use for MPSSE operations. Most
2691 adapters use the default, channel 0, but there are exceptions.
2694 @deffn {Config Command} {ftdi_layout_init} data direction
2695 Specifies the initial values of the FTDI GPIO data and direction registers.
2696 Each value is a 16-bit number corresponding to the concatenation of the high
2697 and low FTDI GPIO registers. The values should be selected based on the
2698 schematics of the adapter, such that all signals are set to safe levels with
2699 minimal impact on the target system. Avoid floating inputs, conflicting outputs
2700 and initially asserted reset signals.
2703 @deffn {Config Command} {ftdi_layout_signal} name [@option{-data}|@option{-ndata} data_mask] [@option{-oe}|@option{-noe} oe_mask]
2704 Creates a signal with the specified @var{name}, controlled by one or more FTDI
2705 GPIO pins via a range of possible buffer connections. The masks are FTDI GPIO
2706 register bitmasks to tell the driver the connection and type of the output
2707 buffer driving the respective signal. @var{data_mask} is the bitmask for the
2708 pin(s) connected to the data input of the output buffer. @option{-ndata} is
2709 used with inverting data inputs and @option{-data} with non-inverting inputs.
2710 The @option{-oe} (or @option{-noe}) option tells where the output-enable (or
2711 not-output-enable) input to the output buffer is connected.
2713 Both @var{data_mask} and @var{oe_mask} need not be specified. For example, a
2714 simple open-collector transistor driver would be specified with @option{-oe}
2715 only. In that case the signal can only be set to drive low or to Hi-Z and the
2716 driver will complain if the signal is set to drive high. Which means that if
2717 it's a reset signal, @command{reset_config} must be specified as
2718 @option{srst_open_drain}, not @option{srst_push_pull}.
2720 A special case is provided when @option{-data} and @option{-oe} is set to the
2721 same bitmask. Then the FTDI pin is considered being connected straight to the
2722 target without any buffer. The FTDI pin is then switched between output and
2723 input as necessary to provide the full set of low, high and Hi-Z
2724 characteristics. In all other cases, the pins specified in a signal definition
2725 are always driven by the FTDI.
2728 @deffn {Command} {ftdi_set_signal} name @option{0}|@option{1}|@option{z}
2729 Set a previously defined signal to the specified level.
2731 @item @option{0}, drive low
2732 @item @option{1}, drive high
2733 @item @option{z}, set to high-impedance
2737 For example adapter definitions, see the configuration files shipped in the
2738 @file{interface/ftdi} directory.
2741 @deffn {Interface Driver} {remote_bitbang}
2742 Drive JTAG from a remote process. This sets up a UNIX or TCP socket connection
2743 with a remote process and sends ASCII encoded bitbang requests to that process
2744 instead of directly driving JTAG.
2746 The remote_bitbang driver is useful for debugging software running on
2747 processors which are being simulated.
2749 @deffn {Config Command} {remote_bitbang_port} number
2750 Specifies the TCP port of the remote process to connect to or 0 to use UNIX
2751 sockets instead of TCP.
2754 @deffn {Config Command} {remote_bitbang_host} hostname
2755 Specifies the hostname of the remote process to connect to using TCP, or the
2756 name of the UNIX socket to use if remote_bitbang_port is 0.
2759 For example, to connect remotely via TCP to the host foobar you might have
2763 interface remote_bitbang
2764 remote_bitbang_port 3335
2765 remote_bitbang_host foobar
2768 To connect to another process running locally via UNIX sockets with socket
2772 interface remote_bitbang
2773 remote_bitbang_port 0
2774 remote_bitbang_host mysocket
2778 @deffn {Interface Driver} {usb_blaster}
2779 USB JTAG/USB-Blaster compatibles over one of the userspace libraries
2780 for FTDI chips. These interfaces have several commands, used to
2781 configure the driver before initializing the JTAG scan chain:
2783 @deffn {Config Command} {usb_blaster_device_desc} description
2784 Provides the USB device description (the @emph{iProduct string})
2785 of the FTDI FT245 device. If not
2786 specified, the FTDI default value is used. This setting is only valid
2787 if compiled with FTD2XX support.
2790 @deffn {Config Command} {usb_blaster_vid_pid} vid pid
2791 The vendor ID and product ID of the FTDI FT245 device. If not specified,
2792 default values are used.
2793 Currently, only one @var{vid}, @var{pid} pair may be given, e.g. for
2794 Altera USB-Blaster (default):
2796 usb_blaster_vid_pid 0x09FB 0x6001
2798 The following VID/PID is for Kolja Waschk's USB JTAG:
2800 usb_blaster_vid_pid 0x16C0 0x06AD
2804 @deffn {Command} {usb_blaster} (@option{pin6}|@option{pin8}) (@option{0}|@option{1})
2805 Sets the state of the unused GPIO pins on USB-Blasters (pins 6 and 8 on the
2806 female JTAG header). These pins can be used as SRST and/or TRST provided the
2807 appropriate connections are made on the target board.
2809 For example, to use pin 6 as SRST (as with an AVR board):
2811 $_TARGETNAME configure -event reset-assert \
2812 "usb_blaster pin6 1; wait 1; usb_blaster pin6 0"
2818 @deffn {Interface Driver} {gw16012}
2819 Gateworks GW16012 JTAG programmer.
2820 This has one driver-specific command:
2822 @deffn {Config Command} {parport_port} [port_number]
2823 Display either the address of the I/O port
2824 (default: 0x378 for LPT1) or the number of the @file{/dev/parport} device.
2825 If a parameter is provided, first switch to use that port.
2826 This is a write-once setting.
2830 @deffn {Interface Driver} {jlink}
2831 Segger J-Link family of USB adapters. It currently supports only the JTAG transport.
2833 @quotation Compatibility Note
2834 Segger released many firmware versions for the many harware versions they
2835 produced. OpenOCD was extensively tested and intended to run on all of them,
2836 but some combinations were reported as incompatible. As a general
2837 recommendation, it is advisable to use the latest firmware version
2838 available for each hardware version. However the current V8 is a moving
2839 target, and Segger firmware versions released after the OpenOCD was
2840 released may not be compatible. In such cases it is recommended to
2841 revert to the last known functional version. For 0.5.0, this is from
2842 "Feb 8 2012 14:30:39", packed with 4.42c. For 0.6.0, the last known
2843 version is from "May 3 2012 18:36:22", packed with 4.46f.
2846 @deffn {Command} {jlink caps}
2847 Display the device firmware capabilities.
2849 @deffn {Command} {jlink info}
2850 Display various device information, like hardware version, firmware version, current bus status.
2852 @deffn {Command} {jlink hw_jtag} [@option{2}|@option{3}]
2853 Set the JTAG protocol version to be used. Without argument, show the actual JTAG protocol version.
2855 @deffn {Command} {jlink config}
2856 Display the J-Link configuration.
2858 @deffn {Command} {jlink config kickstart} [val]
2859 Set the Kickstart power on JTAG-pin 19. Without argument, show the Kickstart configuration.
2861 @deffn {Command} {jlink config mac_address} [@option{ff:ff:ff:ff:ff:ff}]
2862 Set the MAC address of the J-Link Pro. Without argument, show the MAC address.
2864 @deffn {Command} {jlink config ip} [@option{A.B.C.D}(@option{/E}|@option{F.G.H.I})]
2865 Set the IP configuration of the J-Link Pro, where A.B.C.D is the IP address,
2866 E the bit of the subnet mask and
2867 F.G.H.I the subnet mask. Without arguments, show the IP configuration.
2869 @deffn {Command} {jlink config usb_address} [@option{0x00} to @option{0x03} or @option{0xff}]
2870 Set the USB address; this will also change the product id. Without argument, show the USB address.
2872 @deffn {Command} {jlink config reset}
2873 Reset the current configuration.
2875 @deffn {Command} {jlink config save}
2876 Save the current configuration to the internal persistent storage.
2878 @deffn {Config} {jlink pid} val
2879 Set the USB PID of the interface. As a configuration command, it can be used only before 'init'.
2883 @deffn {Interface Driver} {parport}
2884 Supports PC parallel port bit-banging cables:
2885 Wigglers, PLD download cable, and more.
2886 These interfaces have several commands, used to configure the driver
2887 before initializing the JTAG scan chain:
2889 @deffn {Config Command} {parport_cable} name
2890 Set the layout of the parallel port cable used to connect to the target.
2891 This is a write-once setting.
2892 Currently valid cable @var{name} values include:
2895 @item @b{altium} Altium Universal JTAG cable.
2896 @item @b{arm-jtag} Same as original wiggler except SRST and
2897 TRST connections reversed and TRST is also inverted.
2898 @item @b{chameleon} The Amontec Chameleon's CPLD when operated
2899 in configuration mode. This is only used to
2900 program the Chameleon itself, not a connected target.
2901 @item @b{dlc5} The Xilinx Parallel cable III.
2902 @item @b{flashlink} The ST Parallel cable.
2903 @item @b{lattice} Lattice ispDOWNLOAD Cable
2904 @item @b{old_amt_wiggler} The Wiggler configuration that comes with
2906 Amontec's Chameleon Programmer. The new version available from
2907 the website uses the original Wiggler layout ('@var{wiggler}')
2908 @item @b{triton} The parallel port adapter found on the
2909 ``Karo Triton 1 Development Board''.
2910 This is also the layout used by the HollyGates design
2911 (see @uref{http://www.lartmaker.nl/projects/jtag/}).
2912 @item @b{wiggler} The original Wiggler layout, also supported by
2913 several clones, such as the Olimex ARM-JTAG
2914 @item @b{wiggler2} Same as original wiggler except an led is fitted on D5.
2915 @item @b{wiggler_ntrst_inverted} Same as original wiggler except TRST is inverted.
2919 @deffn {Config Command} {parport_port} [port_number]
2920 Display either the address of the I/O port
2921 (default: 0x378 for LPT1) or the number of the @file{/dev/parport} device.
2922 If a parameter is provided, first switch to use that port.
2923 This is a write-once setting.
2925 When using PPDEV to access the parallel port, use the number of the parallel port:
2926 @option{parport_port 0} (the default). If @option{parport_port 0x378} is specified
2927 you may encounter a problem.
2930 @deffn Command {parport_toggling_time} [nanoseconds]
2931 Displays how many nanoseconds the hardware needs to toggle TCK;
2932 the parport driver uses this value to obey the
2933 @command{adapter_khz} configuration.
2934 When the optional @var{nanoseconds} parameter is given,
2935 that setting is changed before displaying the current value.
2937 The default setting should work reasonably well on commodity PC hardware.
2938 However, you may want to calibrate for your specific hardware.
2940 To measure the toggling time with a logic analyzer or a digital storage
2941 oscilloscope, follow the procedure below:
2943 > parport_toggling_time 1000
2946 This sets the maximum JTAG clock speed of the hardware, but
2947 the actual speed probably deviates from the requested 500 kHz.
2948 Now, measure the time between the two closest spaced TCK transitions.
2949 You can use @command{runtest 1000} or something similar to generate a
2950 large set of samples.
2951 Update the setting to match your measurement:
2953 > parport_toggling_time <measured nanoseconds>
2955 Now the clock speed will be a better match for @command{adapter_khz rate}
2956 commands given in OpenOCD scripts and event handlers.
2958 You can do something similar with many digital multimeters, but note
2959 that you'll probably need to run the clock continuously for several
2960 seconds before it decides what clock rate to show. Adjust the
2961 toggling time up or down until the measured clock rate is a good
2962 match for the adapter_khz rate you specified; be conservative.
2966 @deffn {Config Command} {parport_write_on_exit} (@option{on}|@option{off})
2967 This will configure the parallel driver to write a known
2968 cable-specific value to the parallel interface on exiting OpenOCD.
2971 For example, the interface configuration file for a
2972 classic ``Wiggler'' cable on LPT2 might look something like this:
2977 parport_cable wiggler
2981 @deffn {Interface Driver} {presto}
2982 ASIX PRESTO USB JTAG programmer.
2983 @deffn {Config Command} {presto_serial} serial_string
2984 Configures the USB serial number of the Presto device to use.
2988 @deffn {Interface Driver} {rlink}
2989 Raisonance RLink USB adapter
2992 @deffn {Interface Driver} {usbprog}
2993 usbprog is a freely programmable USB adapter.
2996 @deffn {Interface Driver} {vsllink}
2997 vsllink is part of Versaloon which is a versatile USB programmer.
3000 This defines quite a few driver-specific commands,
3001 which are not currently documented here.
3005 @deffn {Interface Driver} {hla}
3006 This is a driver that supports multiple High Level Adapters.
3007 This type of adapter does not expose some of the lower level api's
3008 that OpenOCD would normally use to access the target.
3010 Currently supported adapters include the ST STLINK and TI ICDI.
3012 @deffn {Config Command} {hla_device_desc} description
3013 Currently Not Supported.
3016 @deffn {Config Command} {hla_serial} serial
3017 Currently Not Supported.
3020 @deffn {Config Command} {hla_layout} (@option{stlink}|@option{icdi})
3021 Specifies the adapter layout to use.
3024 @deffn {Config Command} {hla_vid_pid} vid pid
3025 The vendor ID and product ID of the device.
3028 @deffn {Config Command} {stlink_api} api_level
3029 Manually sets the stlink api used, valid options are 1 or 2. (@b{STLINK Only}).
3032 @deffn {Config Command} {trace} output_file_path source_clock_hz
3033 Enable SWO tracing (if supported), trace data is appended to the specified
3034 output file and the file is created if it does not exist. The source clock
3035 rate for the trace port must be specified, this is typically the CPU clock
3040 @deffn {Interface Driver} {opendous}
3041 opendous-jtag is a freely programmable USB adapter.
3044 @deffn {Interface Driver} {ulink}
3045 This is the Keil ULINK v1 JTAG debugger.
3048 @deffn {Interface Driver} {ZY1000}
3049 This is the Zylin ZY1000 JTAG debugger.
3053 This defines some driver-specific commands,
3054 which are not currently documented here.
3057 @deffn Command power [@option{on}|@option{off}]
3058 Turn power switch to target on/off.
3059 No arguments: print status.
3062 @deffn {Interface Driver} {bcm2835gpio}
3063 This SoC is present in Raspberry Pi which is a cheap single-board computer
3064 exposing some GPIOs on its expansion header.
3066 The driver accesses memory-mapped GPIO peripheral registers directly
3067 for maximum performance, but the only possible race condition is for
3068 the pins' modes/muxing (which is highly unlikely), so it should be
3069 able to coexist nicely with both sysfs bitbanging and various
3070 peripherals' kernel drivers. The driver restores the previous
3071 configuration on exit.
3073 See @file{interface/raspberrypi-native.cfg} for a sample config and
3078 @section Transport Configuration
3080 As noted earlier, depending on the version of OpenOCD you use,
3081 and the debug adapter you are using,
3082 several transports may be available to
3083 communicate with debug targets (or perhaps to program flash memory).
3084 @deffn Command {transport list}
3085 displays the names of the transports supported by this
3089 @deffn Command {transport select} transport_name
3090 Select which of the supported transports to use in this OpenOCD session.
3091 The transport must be supported by the debug adapter hardware and by the
3092 version of OpenOCD you are using (including the adapter's driver).
3093 No arguments: returns name of session's selected transport.
3096 @subsection JTAG Transport
3098 JTAG is the original transport supported by OpenOCD, and most
3099 of the OpenOCD commands support it.
3100 JTAG transports expose a chain of one or more Test Access Points (TAPs),
3101 each of which must be explicitly declared.
3102 JTAG supports both debugging and boundary scan testing.
3103 Flash programming support is built on top of debug support.
3104 @subsection SWD Transport
3106 @cindex Serial Wire Debug
3107 SWD (Serial Wire Debug) is an ARM-specific transport which exposes one
3108 Debug Access Point (DAP, which must be explicitly declared.
3109 (SWD uses fewer signal wires than JTAG.)
3110 SWD is debug-oriented, and does not support boundary scan testing.
3111 Flash programming support is built on top of debug support.
3112 (Some processors support both JTAG and SWD.)
3113 @deffn Command {swd newdap} ...
3114 Declares a single DAP which uses SWD transport.
3115 Parameters are currently the same as "jtag newtap" but this is
3118 @deffn Command {swd wcr trn prescale}
3119 Updates TRN (turnaraound delay) and prescaling.fields of the
3120 Wire Control Register (WCR).
3121 No parameters: displays current settings.
3124 @subsection SPI Transport
3126 @cindex Serial Peripheral Interface
3127 The Serial Peripheral Interface (SPI) is a general purpose transport
3128 which uses four wire signaling. Some processors use it as part of a
3129 solution for flash programming.
3133 JTAG clock setup is part of system setup.
3134 It @emph{does not belong with interface setup} since any interface
3135 only knows a few of the constraints for the JTAG clock speed.
3136 Sometimes the JTAG speed is
3137 changed during the target initialization process: (1) slow at
3138 reset, (2) program the CPU clocks, (3) run fast.
3139 Both the "slow" and "fast" clock rates are functions of the
3140 oscillators used, the chip, the board design, and sometimes
3141 power management software that may be active.
3143 The speed used during reset, and the scan chain verification which
3144 follows reset, can be adjusted using a @code{reset-start}
3145 target event handler.
3146 It can then be reconfigured to a faster speed by a
3147 @code{reset-init} target event handler after it reprograms those
3148 CPU clocks, or manually (if something else, such as a boot loader,
3149 sets up those clocks).
3150 @xref{targetevents,,Target Events}.
3151 When the initial low JTAG speed is a chip characteristic, perhaps
3152 because of a required oscillator speed, provide such a handler
3153 in the target config file.
3154 When that speed is a function of a board-specific characteristic
3155 such as which speed oscillator is used, it belongs in the board
3156 config file instead.
3157 In both cases it's safest to also set the initial JTAG clock rate
3158 to that same slow speed, so that OpenOCD never starts up using a
3159 clock speed that's faster than the scan chain can support.
3163 $_TARGET.cpu configure -event reset-start @{ jtag_rclk 3000 @}
3166 If your system supports adaptive clocking (RTCK), configuring
3167 JTAG to use that is probably the most robust approach.
3168 However, it introduces delays to synchronize clocks; so it
3169 may not be the fastest solution.
3171 @b{NOTE:} Script writers should consider using @command{jtag_rclk}
3172 instead of @command{adapter_khz}, but only for (ARM) cores and boards
3173 which support adaptive clocking.
3175 @deffn {Command} adapter_khz max_speed_kHz
3176 A non-zero speed is in KHZ. Hence: 3000 is 3mhz.
3177 JTAG interfaces usually support a limited number of
3178 speeds. The speed actually used won't be faster
3179 than the speed specified.
3181 Chip data sheets generally include a top JTAG clock rate.
3182 The actual rate is often a function of a CPU core clock,
3183 and is normally less than that peak rate.
3184 For example, most ARM cores accept at most one sixth of the CPU clock.
3186 Speed 0 (khz) selects RTCK method.
3187 @xref{faqrtck,,FAQ RTCK}.
3188 If your system uses RTCK, you won't need to change the
3189 JTAG clocking after setup.
3190 Not all interfaces, boards, or targets support ``rtck''.
3191 If the interface device can not
3192 support it, an error is returned when you try to use RTCK.
3195 @defun jtag_rclk fallback_speed_kHz
3196 @cindex adaptive clocking
3198 This Tcl proc (defined in @file{startup.tcl}) attempts to enable RTCK/RCLK.
3199 If that fails (maybe the interface, board, or target doesn't
3200 support it), falls back to the specified frequency.
3202 # Fall back to 3mhz if RTCK is not supported
3207 @node Reset Configuration
3208 @chapter Reset Configuration
3209 @cindex Reset Configuration
3211 Every system configuration may require a different reset
3212 configuration. This can also be quite confusing.
3213 Resets also interact with @var{reset-init} event handlers,
3214 which do things like setting up clocks and DRAM, and
3215 JTAG clock rates. (@xref{jtagspeed,,JTAG Speed}.)
3216 They can also interact with JTAG routers.
3217 Please see the various board files for examples.
3220 To maintainers and integrators:
3221 Reset configuration touches several things at once.
3222 Normally the board configuration file
3223 should define it and assume that the JTAG adapter supports
3224 everything that's wired up to the board's JTAG connector.
3226 However, the target configuration file could also make note
3227 of something the silicon vendor has done inside the chip,
3228 which will be true for most (or all) boards using that chip.
3229 And when the JTAG adapter doesn't support everything, the
3230 user configuration file will need to override parts of
3231 the reset configuration provided by other files.
3234 @section Types of Reset
3236 There are many kinds of reset possible through JTAG, but
3237 they may not all work with a given board and adapter.
3238 That's part of why reset configuration can be error prone.
3242 @emph{System Reset} ... the @emph{SRST} hardware signal
3243 resets all chips connected to the JTAG adapter, such as processors,
3244 power management chips, and I/O controllers. Normally resets triggered
3245 with this signal behave exactly like pressing a RESET button.
3247 @emph{JTAG TAP Reset} ... the @emph{TRST} hardware signal resets
3248 just the TAP controllers connected to the JTAG adapter.
3249 Such resets should not be visible to the rest of the system; resetting a
3250 device's TAP controller just puts that controller into a known state.
3252 @emph{Emulation Reset} ... many devices can be reset through JTAG
3253 commands. These resets are often distinguishable from system
3254 resets, either explicitly (a "reset reason" register says so)
3255 or implicitly (not all parts of the chip get reset).
3257 @emph{Other Resets} ... system-on-chip devices often support
3258 several other types of reset.
3259 You may need to arrange that a watchdog timer stops
3260 while debugging, preventing a watchdog reset.
3261 There may be individual module resets.
3264 In the best case, OpenOCD can hold SRST, then reset
3265 the TAPs via TRST and send commands through JTAG to halt the
3266 CPU at the reset vector before the 1st instruction is executed.
3267 Then when it finally releases the SRST signal, the system is
3268 halted under debugger control before any code has executed.
3269 This is the behavior required to support the @command{reset halt}
3270 and @command{reset init} commands; after @command{reset init} a
3271 board-specific script might do things like setting up DRAM.
3272 (@xref{resetcommand,,Reset Command}.)
3274 @anchor{srstandtrstissues}
3275 @section SRST and TRST Issues
3277 Because SRST and TRST are hardware signals, they can have a
3278 variety of system-specific constraints. Some of the most
3283 @item @emph{Signal not available} ... Some boards don't wire
3284 SRST or TRST to the JTAG connector. Some JTAG adapters don't
3285 support such signals even if they are wired up.
3286 Use the @command{reset_config} @var{signals} options to say
3287 when either of those signals is not connected.
3288 When SRST is not available, your code might not be able to rely
3289 on controllers having been fully reset during code startup.
3290 Missing TRST is not a problem, since JTAG-level resets can
3291 be triggered using with TMS signaling.
3293 @item @emph{Signals shorted} ... Sometimes a chip, board, or
3294 adapter will connect SRST to TRST, instead of keeping them separate.
3295 Use the @command{reset_config} @var{combination} options to say
3296 when those signals aren't properly independent.
3298 @item @emph{Timing} ... Reset circuitry like a resistor/capacitor
3299 delay circuit, reset supervisor, or on-chip features can extend
3300 the effect of a JTAG adapter's reset for some time after the adapter
3301 stops issuing the reset. For example, there may be chip or board
3302 requirements that all reset pulses last for at least a
3303 certain amount of time; and reset buttons commonly have
3304 hardware debouncing.
3305 Use the @command{adapter_nsrst_delay} and @command{jtag_ntrst_delay}
3306 commands to say when extra delays are needed.
3308 @item @emph{Drive type} ... Reset lines often have a pullup
3309 resistor, letting the JTAG interface treat them as open-drain
3310 signals. But that's not a requirement, so the adapter may need
3311 to use push/pull output drivers.
3312 Also, with weak pullups it may be advisable to drive
3313 signals to both levels (push/pull) to minimize rise times.
3314 Use the @command{reset_config} @var{trst_type} and
3315 @var{srst_type} parameters to say how to drive reset signals.
3317 @item @emph{Special initialization} ... Targets sometimes need
3318 special JTAG initialization sequences to handle chip-specific
3319 issues (not limited to errata).
3320 For example, certain JTAG commands might need to be issued while
3321 the system as a whole is in a reset state (SRST active)
3322 but the JTAG scan chain is usable (TRST inactive).
3323 Many systems treat combined assertion of SRST and TRST as a
3324 trigger for a harder reset than SRST alone.
3325 Such custom reset handling is discussed later in this chapter.
3328 There can also be other issues.
3329 Some devices don't fully conform to the JTAG specifications.
3330 Trivial system-specific differences are common, such as
3331 SRST and TRST using slightly different names.
3332 There are also vendors who distribute key JTAG documentation for
3333 their chips only to developers who have signed a Non-Disclosure
3336 Sometimes there are chip-specific extensions like a requirement to use
3337 the normally-optional TRST signal (precluding use of JTAG adapters which
3338 don't pass TRST through), or needing extra steps to complete a TAP reset.
3340 In short, SRST and especially TRST handling may be very finicky,
3341 needing to cope with both architecture and board specific constraints.
3343 @section Commands for Handling Resets
3345 @deffn {Command} adapter_nsrst_assert_width milliseconds
3346 Minimum amount of time (in milliseconds) OpenOCD should wait
3347 after asserting nSRST (active-low system reset) before
3348 allowing it to be deasserted.
3351 @deffn {Command} adapter_nsrst_delay milliseconds
3352 How long (in milliseconds) OpenOCD should wait after deasserting
3353 nSRST (active-low system reset) before starting new JTAG operations.
3354 When a board has a reset button connected to SRST line it will
3355 probably have hardware debouncing, implying you should use this.
3358 @deffn {Command} jtag_ntrst_assert_width milliseconds
3359 Minimum amount of time (in milliseconds) OpenOCD should wait
3360 after asserting nTRST (active-low JTAG TAP reset) before
3361 allowing it to be deasserted.
3364 @deffn {Command} jtag_ntrst_delay milliseconds
3365 How long (in milliseconds) OpenOCD should wait after deasserting
3366 nTRST (active-low JTAG TAP reset) before starting new JTAG operations.
3369 @deffn {Command} reset_config mode_flag ...
3370 This command displays or modifies the reset configuration
3371 of your combination of JTAG board and target in target
3372 configuration scripts.
3374 Information earlier in this section describes the kind of problems
3375 the command is intended to address (@pxref{srstandtrstissues,,SRST and TRST Issues}).
3376 As a rule this command belongs only in board config files,
3377 describing issues like @emph{board doesn't connect TRST};
3378 or in user config files, addressing limitations derived
3379 from a particular combination of interface and board.
3380 (An unlikely example would be using a TRST-only adapter
3381 with a board that only wires up SRST.)
3383 The @var{mode_flag} options can be specified in any order, but only one
3384 of each type -- @var{signals}, @var{combination}, @var{gates},
3385 @var{trst_type}, @var{srst_type} and @var{connect_type}
3386 -- may be specified at a time.
3387 If you don't provide a new value for a given type, its previous
3388 value (perhaps the default) is unchanged.
3389 For example, this means that you don't need to say anything at all about
3390 TRST just to declare that if the JTAG adapter should want to drive SRST,
3391 it must explicitly be driven high (@option{srst_push_pull}).
3395 @var{signals} can specify which of the reset signals are connected.
3396 For example, If the JTAG interface provides SRST, but the board doesn't
3397 connect that signal properly, then OpenOCD can't use it.
3398 Possible values are @option{none} (the default), @option{trst_only},
3399 @option{srst_only} and @option{trst_and_srst}.
3402 If your board provides SRST and/or TRST through the JTAG connector,
3403 you must declare that so those signals can be used.
3407 The @var{combination} is an optional value specifying broken reset
3408 signal implementations.
3409 The default behaviour if no option given is @option{separate},
3410 indicating everything behaves normally.
3411 @option{srst_pulls_trst} states that the
3412 test logic is reset together with the reset of the system (e.g. NXP
3413 LPC2000, "broken" board layout), @option{trst_pulls_srst} says that
3414 the system is reset together with the test logic (only hypothetical, I
3415 haven't seen hardware with such a bug, and can be worked around).
3416 @option{combined} implies both @option{srst_pulls_trst} and
3417 @option{trst_pulls_srst}.
3420 The @var{gates} tokens control flags that describe some cases where
3421 JTAG may be unvailable during reset.
3422 @option{srst_gates_jtag} (default)
3423 indicates that asserting SRST gates the
3424 JTAG clock. This means that no communication can happen on JTAG
3425 while SRST is asserted.
3426 Its converse is @option{srst_nogate}, indicating that JTAG commands
3427 can safely be issued while SRST is active.
3430 The @var{connect_type} tokens control flags that describe some cases where
3431 SRST is asserted while connecting to the target. @option{srst_nogate}
3432 is required to use this option.
3433 @option{connect_deassert_srst} (default)
3434 indicates that SRST will not be asserted while connecting to the target.
3435 Its converse is @option{connect_assert_srst}, indicating that SRST will
3436 be asserted before any target connection.
3437 Only some targets support this feature, STM32 and STR9 are examples.
3438 This feature is useful if you are unable to connect to your target due
3439 to incorrect options byte config or illegal program execution.
3442 The optional @var{trst_type} and @var{srst_type} parameters allow the
3443 driver mode of each reset line to be specified. These values only affect
3444 JTAG interfaces with support for different driver modes, like the Amontec
3445 JTAGkey and JTAG Accelerator. Also, they are necessarily ignored if the
3446 relevant signal (TRST or SRST) is not connected.
3450 Possible @var{trst_type} driver modes for the test reset signal (TRST)
3451 are the default @option{trst_push_pull}, and @option{trst_open_drain}.
3452 Most boards connect this signal to a pulldown, so the JTAG TAPs
3453 never leave reset unless they are hooked up to a JTAG adapter.
3456 Possible @var{srst_type} driver modes for the system reset signal (SRST)
3457 are the default @option{srst_open_drain}, and @option{srst_push_pull}.
3458 Most boards connect this signal to a pullup, and allow the
3459 signal to be pulled low by various events including system
3460 powerup and pressing a reset button.
3464 @section Custom Reset Handling
3467 OpenOCD has several ways to help support the various reset
3468 mechanisms provided by chip and board vendors.
3469 The commands shown in the previous section give standard parameters.
3470 There are also @emph{event handlers} associated with TAPs or Targets.
3471 Those handlers are Tcl procedures you can provide, which are invoked
3472 at particular points in the reset sequence.
3474 @emph{When SRST is not an option} you must set
3475 up a @code{reset-assert} event handler for your target.
3476 For example, some JTAG adapters don't include the SRST signal;
3477 and some boards have multiple targets, and you won't always
3478 want to reset everything at once.
3480 After configuring those mechanisms, you might still
3481 find your board doesn't start up or reset correctly.
3482 For example, maybe it needs a slightly different sequence
3483 of SRST and/or TRST manipulations, because of quirks that
3484 the @command{reset_config} mechanism doesn't address;
3485 or asserting both might trigger a stronger reset, which
3486 needs special attention.
3488 Experiment with lower level operations, such as @command{jtag_reset}
3489 and the @command{jtag arp_*} operations shown here,
3490 to find a sequence of operations that works.
3491 @xref{JTAG Commands}.
3492 When you find a working sequence, it can be used to override
3493 @command{jtag_init}, which fires during OpenOCD startup
3494 (@pxref{configurationstage,,Configuration Stage});
3495 or @command{init_reset}, which fires during reset processing.
3497 You might also want to provide some project-specific reset
3498 schemes. For example, on a multi-target board the standard
3499 @command{reset} command would reset all targets, but you
3500 may need the ability to reset only one target at time and
3501 thus want to avoid using the board-wide SRST signal.
3503 @deffn {Overridable Procedure} init_reset mode
3504 This is invoked near the beginning of the @command{reset} command,
3505 usually to provide as much of a cold (power-up) reset as practical.
3506 By default it is also invoked from @command{jtag_init} if
3507 the scan chain does not respond to pure JTAG operations.
3508 The @var{mode} parameter is the parameter given to the
3509 low level reset command (@option{halt},
3510 @option{init}, or @option{run}), @option{setup},
3511 or potentially some other value.
3513 The default implementation just invokes @command{jtag arp_init-reset}.
3514 Replacements will normally build on low level JTAG
3515 operations such as @command{jtag_reset}.
3516 Operations here must not address individual TAPs
3517 (or their associated targets)
3518 until the JTAG scan chain has first been verified to work.
3520 Implementations must have verified the JTAG scan chain before
3522 This is done by calling @command{jtag arp_init}
3523 (or @command{jtag arp_init-reset}).
3526 @deffn Command {jtag arp_init}
3527 This validates the scan chain using just the four
3528 standard JTAG signals (TMS, TCK, TDI, TDO).
3529 It starts by issuing a JTAG-only reset.
3530 Then it performs checks to verify that the scan chain configuration
3531 matches the TAPs it can observe.
3532 Those checks include checking IDCODE values for each active TAP,
3533 and verifying the length of their instruction registers using
3534 TAP @code{-ircapture} and @code{-irmask} values.
3535 If these tests all pass, TAP @code{setup} events are
3536 issued to all TAPs with handlers for that event.
3539 @deffn Command {jtag arp_init-reset}
3540 This uses TRST and SRST to try resetting
3541 everything on the JTAG scan chain
3542 (and anything else connected to SRST).
3543 It then invokes the logic of @command{jtag arp_init}.
3547 @node TAP Declaration
3548 @chapter TAP Declaration
3549 @cindex TAP declaration
3550 @cindex TAP configuration
3552 @emph{Test Access Ports} (TAPs) are the core of JTAG.
3553 TAPs serve many roles, including:
3556 @item @b{Debug Target} A CPU TAP can be used as a GDB debug target
3557 @item @b{Flash Programing} Some chips program the flash directly via JTAG.
3558 Others do it indirectly, making a CPU do it.
3559 @item @b{Program Download} Using the same CPU support GDB uses,
3560 you can initialize a DRAM controller, download code to DRAM, and then
3561 start running that code.
3562 @item @b{Boundary Scan} Most chips support boundary scan, which
3563 helps test for board assembly problems like solder bridges
3564 and missing connections
3567 OpenOCD must know about the active TAPs on your board(s).
3568 Setting up the TAPs is the core task of your configuration files.
3569 Once those TAPs are set up, you can pass their names to code
3570 which sets up CPUs and exports them as GDB targets,
3571 probes flash memory, performs low-level JTAG operations, and more.
3573 @section Scan Chains
3576 TAPs are part of a hardware @dfn{scan chain},
3577 which is daisy chain of TAPs.
3578 They also need to be added to
3579 OpenOCD's software mirror of that hardware list,
3580 giving each member a name and associating other data with it.
3581 Simple scan chains, with a single TAP, are common in
3582 systems with a single microcontroller or microprocessor.
3583 More complex chips may have several TAPs internally.
3584 Very complex scan chains might have a dozen or more TAPs:
3585 several in one chip, more in the next, and connecting
3586 to other boards with their own chips and TAPs.
3588 You can display the list with the @command{scan_chain} command.
3589 (Don't confuse this with the list displayed by the @command{targets}
3590 command, presented in the next chapter.
3591 That only displays TAPs for CPUs which are configured as
3593 Here's what the scan chain might look like for a chip more than one TAP:
3596 TapName Enabled IdCode Expected IrLen IrCap IrMask
3597 -- ------------------ ------- ---------- ---------- ----- ----- ------
3598 0 omap5912.dsp Y 0x03df1d81 0x03df1d81 38 0x01 0x03
3599 1 omap5912.arm Y 0x0692602f 0x0692602f 4 0x01 0x0f
3600 2 omap5912.unknown Y 0x00000000 0x00000000 8 0x01 0x03
3603 OpenOCD can detect some of that information, but not all
3604 of it. @xref{autoprobing,,Autoprobing}.
3605 Unfortunately those TAPs can't always be autoconfigured,
3606 because not all devices provide good support for that.
3607 JTAG doesn't require supporting IDCODE instructions, and
3608 chips with JTAG routers may not link TAPs into the chain
3609 until they are told to do so.
3611 The configuration mechanism currently supported by OpenOCD
3612 requires explicit configuration of all TAP devices using
3613 @command{jtag newtap} commands, as detailed later in this chapter.
3614 A command like this would declare one tap and name it @code{chip1.cpu}:
3617 jtag newtap chip1 cpu -irlen 4 -expected-id 0x3ba00477
3620 Each target configuration file lists the TAPs provided
3622 Board configuration files combine all the targets on a board,
3624 Note that @emph{the order in which TAPs are declared is very important.}
3625 It must match the order in the JTAG scan chain, both inside
3626 a single chip and between them.
3627 @xref{faqtaporder,,FAQ TAP Order}.
3629 For example, the ST Microsystems STR912 chip has
3630 three separate TAPs@footnote{See the ST
3631 document titled: @emph{STR91xFAxxx, Section 3.15 Jtag Interface, Page:
3632 28/102, Figure 3: JTAG chaining inside the STR91xFA}.
3633 @url{http://eu.st.com/stonline/products/literature/ds/13495.pdf}}.
3634 To configure those taps, @file{target/str912.cfg}
3635 includes commands something like this:
3638 jtag newtap str912 flash ... params ...
3639 jtag newtap str912 cpu ... params ...
3640 jtag newtap str912 bs ... params ...
3643 Actual config files use a variable instead of literals like
3644 @option{str912}, to support more than one chip of each type.
3645 @xref{Config File Guidelines}.
3647 @deffn Command {jtag names}
3648 Returns the names of all current TAPs in the scan chain.
3649 Use @command{jtag cget} or @command{jtag tapisenabled}
3650 to examine attributes and state of each TAP.
3652 foreach t [jtag names] @{
3653 puts [format "TAP: %s\n" $t]
3658 @deffn Command {scan_chain}
3659 Displays the TAPs in the scan chain configuration,
3661 The set of TAPs listed by this command is fixed by
3662 exiting the OpenOCD configuration stage,
3663 but systems with a JTAG router can
3664 enable or disable TAPs dynamically.
3667 @c FIXME! "jtag cget" should be able to return all TAP
3668 @c attributes, like "$target_name cget" does for targets.
3670 @c Probably want "jtag eventlist", and a "tap-reset" event
3671 @c (on entry to RESET state).
3676 When TAP objects are declared with @command{jtag newtap},
3677 a @dfn{dotted.name} is created for the TAP, combining the
3678 name of a module (usually a chip) and a label for the TAP.
3679 For example: @code{xilinx.tap}, @code{str912.flash},
3680 @code{omap3530.jrc}, @code{dm6446.dsp}, or @code{stm32.cpu}.
3681 Many other commands use that dotted.name to manipulate or
3682 refer to the TAP. For example, CPU configuration uses the
3683 name, as does declaration of NAND or NOR flash banks.
3685 The components of a dotted name should follow ``C'' symbol
3686 name rules: start with an alphabetic character, then numbers
3687 and underscores are OK; while others (including dots!) are not.
3690 In older code, JTAG TAPs were numbered from 0..N.
3691 This feature is still present.
3692 However its use is highly discouraged, and
3693 should not be relied on; it will be removed by mid-2010.
3694 Update all of your scripts to use TAP names rather than numbers,
3695 by paying attention to the runtime warnings they trigger.
3696 Using TAP numbers in target configuration scripts prevents
3697 reusing those scripts on boards with multiple targets.
3700 @section TAP Declaration Commands
3702 @c shouldn't this be(come) a {Config Command}?
3703 @deffn Command {jtag newtap} chipname tapname configparams...
3704 Declares a new TAP with the dotted name @var{chipname}.@var{tapname},
3705 and configured according to the various @var{configparams}.
3707 The @var{chipname} is a symbolic name for the chip.
3708 Conventionally target config files use @code{$_CHIPNAME},
3709 defaulting to the model name given by the chip vendor but
3712 @cindex TAP naming convention
3713 The @var{tapname} reflects the role of that TAP,
3714 and should follow this convention:
3717 @item @code{bs} -- For boundary scan if this is a seperate TAP;
3718 @item @code{cpu} -- The main CPU of the chip, alternatively
3719 @code{arm} and @code{dsp} on chips with both ARM and DSP CPUs,
3720 @code{arm1} and @code{arm2} on chips two ARMs, and so forth;
3721 @item @code{etb} -- For an embedded trace buffer (example: an ARM ETB11);
3722 @item @code{flash} -- If the chip has a flash TAP, like the str912;
3723 @item @code{jrc} -- For JTAG route controller (example: the ICEpick modules
3724 on many Texas Instruments chips, like the OMAP3530 on Beagleboards);
3725 @item @code{tap} -- Should be used only FPGA or CPLD like devices
3727 @item @code{unknownN} -- If you have no idea what the TAP is for (N is a number);
3728 @item @emph{when in doubt} -- Use the chip maker's name in their data sheet.
3729 For example, the Freescale IMX31 has a SDMA (Smart DMA) with
3730 a JTAG TAP; that TAP should be named @code{sdma}.
3733 Every TAP requires at least the following @var{configparams}:
3736 @item @code{-irlen} @var{NUMBER}
3737 @*The length in bits of the
3738 instruction register, such as 4 or 5 bits.
3741 A TAP may also provide optional @var{configparams}:
3744 @item @code{-disable} (or @code{-enable})
3745 @*Use the @code{-disable} parameter to flag a TAP which is not
3746 linked in to the scan chain after a reset using either TRST
3747 or the JTAG state machine's @sc{reset} state.
3748 You may use @code{-enable} to highlight the default state
3749 (the TAP is linked in).
3750 @xref{enablinganddisablingtaps,,Enabling and Disabling TAPs}.
3751 @item @code{-expected-id} @var{number}
3752 @*A non-zero @var{number} represents a 32-bit IDCODE
3753 which you expect to find when the scan chain is examined.
3754 These codes are not required by all JTAG devices.
3755 @emph{Repeat the option} as many times as required if more than one
3756 ID code could appear (for example, multiple versions).
3757 Specify @var{number} as zero to suppress warnings about IDCODE
3758 values that were found but not included in the list.
3760 Provide this value if at all possible, since it lets OpenOCD
3761 tell when the scan chain it sees isn't right. These values
3762 are provided in vendors' chip documentation, usually a technical
3763 reference manual. Sometimes you may need to probe the JTAG
3764 hardware to find these values.
3765 @xref{autoprobing,,Autoprobing}.
3766 @item @code{-ignore-version}
3767 @*Specify this to ignore the JTAG version field in the @code{-expected-id}
3768 option. When vendors put out multiple versions of a chip, or use the same
3769 JTAG-level ID for several largely-compatible chips, it may be more practical
3770 to ignore the version field than to update config files to handle all of
3771 the various chip IDs. The version field is defined as bit 28-31 of the IDCODE.
3772 @item @code{-ircapture} @var{NUMBER}
3773 @*The bit pattern loaded by the TAP into the JTAG shift register
3774 on entry to the @sc{ircapture} state, such as 0x01.
3775 JTAG requires the two LSBs of this value to be 01.
3776 By default, @code{-ircapture} and @code{-irmask} are set
3777 up to verify that two-bit value. You may provide
3778 additional bits, if you know them, or indicate that
3779 a TAP doesn't conform to the JTAG specification.
3780 @item @code{-irmask} @var{NUMBER}
3781 @*A mask used with @code{-ircapture}
3782 to verify that instruction scans work correctly.
3783 Such scans are not used by OpenOCD except to verify that
3784 there seems to be no problems with JTAG scan chain operations.
3788 @section Other TAP commands
3790 @deffn Command {jtag cget} dotted.name @option{-event} name
3791 @deffnx Command {jtag configure} dotted.name @option{-event} name string
3792 At this writing this TAP attribute
3793 mechanism is used only for event handling.
3794 (It is not a direct analogue of the @code{cget}/@code{configure}
3795 mechanism for debugger targets.)
3796 See the next section for information about the available events.
3798 The @code{configure} subcommand assigns an event handler,
3799 a TCL string which is evaluated when the event is triggered.
3800 The @code{cget} subcommand returns that handler.
3807 OpenOCD includes two event mechanisms.
3808 The one presented here applies to all JTAG TAPs.
3809 The other applies to debugger targets,
3810 which are associated with certain TAPs.
3812 The TAP events currently defined are:
3815 @item @b{post-reset}
3816 @* The TAP has just completed a JTAG reset.
3817 The tap may still be in the JTAG @sc{reset} state.
3818 Handlers for these events might perform initialization sequences
3819 such as issuing TCK cycles, TMS sequences to ensure
3820 exit from the ARM SWD mode, and more.
3822 Because the scan chain has not yet been verified, handlers for these events
3823 @emph{should not issue commands which scan the JTAG IR or DR registers}
3824 of any particular target.
3825 @b{NOTE:} As this is written (September 2009), nothing prevents such access.
3827 @* The scan chain has been reset and verified.
3828 This handler may enable TAPs as needed.
3829 @item @b{tap-disable}
3830 @* The TAP needs to be disabled. This handler should
3831 implement @command{jtag tapdisable}
3832 by issuing the relevant JTAG commands.
3833 @item @b{tap-enable}
3834 @* The TAP needs to be enabled. This handler should
3835 implement @command{jtag tapenable}
3836 by issuing the relevant JTAG commands.
3839 If you need some action after each JTAG reset, which isn't actually
3840 specific to any TAP (since you can't yet trust the scan chain's
3841 contents to be accurate), you might:
3844 jtag configure CHIP.jrc -event post-reset @{
3845 echo "JTAG Reset done"
3846 ... non-scan jtag operations to be done after reset
3851 @anchor{enablinganddisablingtaps}
3852 @section Enabling and Disabling TAPs
3853 @cindex JTAG Route Controller
3856 In some systems, a @dfn{JTAG Route Controller} (JRC)
3857 is used to enable and/or disable specific JTAG TAPs.
3858 Many ARM based chips from Texas Instruments include
3859 an ``ICEpick'' module, which is a JRC.
3860 Such chips include DaVinci and OMAP3 processors.
3862 A given TAP may not be visible until the JRC has been
3863 told to link it into the scan chain; and if the JRC
3864 has been told to unlink that TAP, it will no longer
3866 Such routers address problems that JTAG ``bypass mode''
3870 @item The scan chain can only go as fast as its slowest TAP.
3871 @item Having many TAPs slows instruction scans, since all
3872 TAPs receive new instructions.
3873 @item TAPs in the scan chain must be powered up, which wastes
3874 power and prevents debugging some power management mechanisms.
3877 The IEEE 1149.1 JTAG standard has no concept of a ``disabled'' tap,
3878 as implied by the existence of JTAG routers.
3879 However, the upcoming IEEE 1149.7 framework (layered on top of JTAG)
3880 does include a kind of JTAG router functionality.
3882 @c (a) currently the event handlers don't seem to be able to
3883 @c fail in a way that could lead to no-change-of-state.
3885 In OpenOCD, tap enabling/disabling is invoked by the Tcl commands
3886 shown below, and is implemented using TAP event handlers.
3887 So for example, when defining a TAP for a CPU connected to
3888 a JTAG router, your @file{target.cfg} file
3889 should define TAP event handlers using
3890 code that looks something like this:
3893 jtag configure CHIP.cpu -event tap-enable @{
3894 ... jtag operations using CHIP.jrc
3896 jtag configure CHIP.cpu -event tap-disable @{
3897 ... jtag operations using CHIP.jrc
3901 Then you might want that CPU's TAP enabled almost all the time:
3904 jtag configure $CHIP.jrc -event setup "jtag tapenable $CHIP.cpu"
3907 Note how that particular setup event handler declaration
3908 uses quotes to evaluate @code{$CHIP} when the event is configured.
3909 Using brackets @{ @} would cause it to be evaluated later,
3910 at runtime, when it might have a different value.
3912 @deffn Command {jtag tapdisable} dotted.name
3913 If necessary, disables the tap
3914 by sending it a @option{tap-disable} event.
3915 Returns the string "1" if the tap
3916 specified by @var{dotted.name} is enabled,
3917 and "0" if it is disabled.
3920 @deffn Command {jtag tapenable} dotted.name
3921 If necessary, enables the tap
3922 by sending it a @option{tap-enable} event.
3923 Returns the string "1" if the tap
3924 specified by @var{dotted.name} is enabled,
3925 and "0" if it is disabled.
3928 @deffn Command {jtag tapisenabled} dotted.name
3929 Returns the string "1" if the tap
3930 specified by @var{dotted.name} is enabled,
3931 and "0" if it is disabled.
3934 Humans will find the @command{scan_chain} command more helpful
3935 for querying the state of the JTAG taps.
3939 @anchor{autoprobing}
3940 @section Autoprobing
3942 @cindex JTAG autoprobe
3944 TAP configuration is the first thing that needs to be done
3945 after interface and reset configuration. Sometimes it's
3946 hard finding out what TAPs exist, or how they are identified.
3947 Vendor documentation is not always easy to find and use.
3949 To help you get past such problems, OpenOCD has a limited
3950 @emph{autoprobing} ability to look at the scan chain, doing
3951 a @dfn{blind interrogation} and then reporting the TAPs it finds.
3952 To use this mechanism, start the OpenOCD server with only data
3953 that configures your JTAG interface, and arranges to come up
3954 with a slow clock (many devices don't support fast JTAG clocks
3955 right when they come out of reset).
3957 For example, your @file{openocd.cfg} file might have:
3960 source [find interface/olimex-arm-usb-tiny-h.cfg]
3961 reset_config trst_and_srst
3965 When you start the server without any TAPs configured, it will
3966 attempt to autoconfigure the TAPs. There are two parts to this:
3969 @item @emph{TAP discovery} ...
3970 After a JTAG reset (sometimes a system reset may be needed too),
3971 each TAP's data registers will hold the contents of either the
3972 IDCODE or BYPASS register.
3973 If JTAG communication is working, OpenOCD will see each TAP,
3974 and report what @option{-expected-id} to use with it.
3975 @item @emph{IR Length discovery} ...
3976 Unfortunately JTAG does not provide a reliable way to find out
3977 the value of the @option{-irlen} parameter to use with a TAP
3979 If OpenOCD can discover the length of a TAP's instruction
3980 register, it will report it.
3981 Otherwise you may need to consult vendor documentation, such
3982 as chip data sheets or BSDL files.
3985 In many cases your board will have a simple scan chain with just
3986 a single device. Here's what OpenOCD reported with one board
3987 that's a bit more complex:
3991 There are no enabled taps. AUTO PROBING MIGHT NOT WORK!!
3992 AUTO auto0.tap - use "jtag newtap auto0 tap -expected-id 0x2b900f0f ..."
3993 AUTO auto1.tap - use "jtag newtap auto1 tap -expected-id 0x07926001 ..."
3994 AUTO auto2.tap - use "jtag newtap auto2 tap -expected-id 0x0b73b02f ..."
3995 AUTO auto0.tap - use "... -irlen 4"
3996 AUTO auto1.tap - use "... -irlen 4"
3997 AUTO auto2.tap - use "... -irlen 6"
3998 no gdb ports allocated as no target has been specified
4001 Given that information, you should be able to either find some existing
4002 config files to use, or create your own. If you create your own, you
4003 would configure from the bottom up: first a @file{target.cfg} file
4004 with these TAPs, any targets associated with them, and any on-chip
4005 resources; then a @file{board.cfg} with off-chip resources, clocking,
4008 @node CPU Configuration
4009 @chapter CPU Configuration
4012 This chapter discusses how to set up GDB debug targets for CPUs.
4013 You can also access these targets without GDB
4014 (@pxref{Architecture and Core Commands},
4015 and @ref{targetstatehandling,,Target State handling}) and
4016 through various kinds of NAND and NOR flash commands.
4017 If you have multiple CPUs you can have multiple such targets.
4019 We'll start by looking at how to examine the targets you have,
4020 then look at how to add one more target and how to configure it.
4022 @section Target List
4023 @cindex target, current
4024 @cindex target, list
4026 All targets that have been set up are part of a list,
4027 where each member has a name.
4028 That name should normally be the same as the TAP name.
4029 You can display the list with the @command{targets}
4031 This display often has only one CPU; here's what it might
4032 look like with more than one:
4034 TargetName Type Endian TapName State
4035 -- ------------------ ---------- ------ ------------------ ------------
4036 0* at91rm9200.cpu arm920t little at91rm9200.cpu running
4037 1 MyTarget cortex_m little mychip.foo tap-disabled
4040 One member of that list is the @dfn{current target}, which
4041 is implicitly referenced by many commands.
4042 It's the one marked with a @code{*} near the target name.
4043 In particular, memory addresses often refer to the address
4044 space seen by that current target.
4045 Commands like @command{mdw} (memory display words)
4046 and @command{flash erase_address} (erase NOR flash blocks)
4047 are examples; and there are many more.
4049 Several commands let you examine the list of targets:
4051 @deffn Command {target count}
4052 @emph{Note: target numbers are deprecated; don't use them.
4053 They will be removed shortly after August 2010, including this command.
4054 Iterate target using @command{target names}, not by counting.}
4056 Returns the number of targets, @math{N}.
4057 The highest numbered target is @math{N - 1}.
4059 set c [target count]
4060 for @{ set x 0 @} @{ $x < $c @} @{ incr x @} @{
4061 # Assuming you have created this function
4062 print_target_details $x
4067 @deffn Command {target current}
4068 Returns the name of the current target.
4071 @deffn Command {target names}
4072 Lists the names of all current targets in the list.
4074 foreach t [target names] @{
4075 puts [format "Target: %s\n" $t]
4080 @deffn Command {target number} number
4081 @emph{Note: target numbers are deprecated; don't use them.
4082 They will be removed shortly after August 2010, including this command.}
4084 The list of targets is numbered starting at zero.
4085 This command returns the name of the target at index @var{number}.
4087 set thename [target number $x]
4088 puts [format "Target %d is: %s\n" $x $thename]
4092 @c yep, "target list" would have been better.
4093 @c plus maybe "target setdefault".
4095 @deffn Command targets [name]
4096 @emph{Note: the name of this command is plural. Other target
4097 command names are singular.}
4099 With no parameter, this command displays a table of all known
4100 targets in a user friendly form.
4102 With a parameter, this command sets the current target to
4103 the given target with the given @var{name}; this is
4104 only relevant on boards which have more than one target.
4107 @section Target CPU Types and Variants
4112 Each target has a @dfn{CPU type}, as shown in the output of
4113 the @command{targets} command. You need to specify that type
4114 when calling @command{target create}.
4115 The CPU type indicates more than just the instruction set.
4116 It also indicates how that instruction set is implemented,
4117 what kind of debug support it integrates,
4118 whether it has an MMU (and if so, what kind),
4119 what core-specific commands may be available
4120 (@pxref{Architecture and Core Commands}),
4123 For some CPU types, OpenOCD also defines @dfn{variants} which
4124 indicate differences that affect their handling.
4125 For example, a particular implementation bug might need to be
4126 worked around in some chip versions.
4128 It's easy to see what target types are supported,
4129 since there's a command to list them.
4130 However, there is currently no way to list what target variants
4131 are supported (other than by reading the OpenOCD source code).
4133 @anchor{targettypes}
4134 @deffn Command {target types}
4135 Lists all supported target types.
4136 At this writing, the supported CPU types and variants are:
4139 @item @code{arm11} -- this is a generation of ARMv6 cores
4140 @item @code{arm720t} -- this is an ARMv4 core with an MMU
4141 @item @code{arm7tdmi} -- this is an ARMv4 core
4142 @item @code{arm920t} -- this is an ARMv4 core with an MMU
4143 @item @code{arm926ejs} -- this is an ARMv5 core with an MMU
4144 @item @code{arm966e} -- this is an ARMv5 core
4145 @item @code{arm9tdmi} -- this is an ARMv4 core
4146 @item @code{avr} -- implements Atmel's 8-bit AVR instruction set.
4147 (Support for this is preliminary and incomplete.)
4148 @item @code{cortex_a} -- this is an ARMv7 core with an MMU
4149 @item @code{cortex_m} -- this is an ARMv7 core, supporting only the
4150 compact Thumb2 instruction set.
4151 @item @code{dragonite} -- resembles arm966e
4152 @item @code{dsp563xx} -- implements Freescale's 24-bit DSP.
4153 (Support for this is still incomplete.)
4154 @item @code{fa526} -- resembles arm920 (w/o Thumb)
4155 @item @code{feroceon} -- resembles arm926
4156 @item @code{mips_m4k} -- a MIPS core. This supports one variant:
4157 @item @code{xscale} -- this is actually an architecture,
4158 not a CPU type. It is based on the ARMv5 architecture.
4159 There are several variants defined:
4161 @item @code{ixp42x}, @code{ixp45x}, @code{ixp46x},
4162 @code{pxa27x} ... instruction register length is 7 bits
4163 @item @code{pxa250}, @code{pxa255},
4164 @code{pxa26x} ... instruction register length is 5 bits
4165 @item @code{pxa3xx} ... instruction register length is 11 bits
4170 To avoid being confused by the variety of ARM based cores, remember
4171 this key point: @emph{ARM is a technology licencing company}.
4172 (See: @url{http://www.arm.com}.)
4173 The CPU name used by OpenOCD will reflect the CPU design that was
4174 licenced, not a vendor brand which incorporates that design.
4175 Name prefixes like arm7, arm9, arm11, and cortex
4176 reflect design generations;
4177 while names like ARMv4, ARMv5, ARMv6, and ARMv7
4178 reflect an architecture version implemented by a CPU design.
4180 @anchor{targetconfiguration}
4181 @section Target Configuration
4183 Before creating a ``target'', you must have added its TAP to the scan chain.
4184 When you've added that TAP, you will have a @code{dotted.name}
4185 which is used to set up the CPU support.
4186 The chip-specific configuration file will normally configure its CPU(s)
4187 right after it adds all of the chip's TAPs to the scan chain.
4189 Although you can set up a target in one step, it's often clearer if you
4190 use shorter commands and do it in two steps: create it, then configure
4192 All operations on the target after it's created will use a new
4193 command, created as part of target creation.
4195 The two main things to configure after target creation are
4196 a work area, which usually has target-specific defaults even
4197 if the board setup code overrides them later;
4198 and event handlers (@pxref{targetevents,,Target Events}), which tend
4199 to be much more board-specific.
4200 The key steps you use might look something like this
4203 target create MyTarget cortex_m -chain-position mychip.cpu
4204 $MyTarget configure -work-area-phys 0x08000 -work-area-size 8096
4205 $MyTarget configure -event reset-deassert-pre @{ jtag_rclk 5 @}
4206 $MyTarget configure -event reset-init @{ myboard_reinit @}
4209 You should specify a working area if you can; typically it uses some
4211 Such a working area can speed up many things, including bulk
4212 writes to target memory;
4213 flash operations like checking to see if memory needs to be erased;
4214 GDB memory checksumming;
4218 On more complex chips, the work area can become
4219 inaccessible when application code
4220 (such as an operating system)
4221 enables or disables the MMU.
4222 For example, the particular MMU context used to acess the virtual
4223 address will probably matter ... and that context might not have
4224 easy access to other addresses needed.
4225 At this writing, OpenOCD doesn't have much MMU intelligence.
4228 It's often very useful to define a @code{reset-init} event handler.
4229 For systems that are normally used with a boot loader,
4230 common tasks include updating clocks and initializing memory
4232 That may be needed to let you write the boot loader into flash,
4233 in order to ``de-brick'' your board; or to load programs into
4234 external DDR memory without having run the boot loader.
4236 @deffn Command {target create} target_name type configparams...
4237 This command creates a GDB debug target that refers to a specific JTAG tap.
4238 It enters that target into a list, and creates a new
4239 command (@command{@var{target_name}}) which is used for various
4240 purposes including additional configuration.
4243 @item @var{target_name} ... is the name of the debug target.
4244 By convention this should be the same as the @emph{dotted.name}
4245 of the TAP associated with this target, which must be specified here
4246 using the @code{-chain-position @var{dotted.name}} configparam.
4248 This name is also used to create the target object command,
4249 referred to here as @command{$target_name},
4250 and in other places the target needs to be identified.
4251 @item @var{type} ... specifies the target type. @xref{targettypes,,target types}.
4252 @item @var{configparams} ... all parameters accepted by
4253 @command{$target_name configure} are permitted.
4254 If the target is big-endian, set it here with @code{-endian big}.
4255 If the variant matters, set it here with @code{-variant}.
4257 You @emph{must} set the @code{-chain-position @var{dotted.name}} here.
4261 @deffn Command {$target_name configure} configparams...
4262 The options accepted by this command may also be
4263 specified as parameters to @command{target create}.
4264 Their values can later be queried one at a time by
4265 using the @command{$target_name cget} command.
4267 @emph{Warning:} changing some of these after setup is dangerous.
4268 For example, moving a target from one TAP to another;
4269 and changing its endianness or variant.
4273 @item @code{-chain-position} @var{dotted.name} -- names the TAP
4274 used to access this target.
4276 @item @code{-endian} (@option{big}|@option{little}) -- specifies
4277 whether the CPU uses big or little endian conventions
4279 @item @code{-event} @var{event_name} @var{event_body} --
4280 @xref{targetevents,,Target Events}.
4281 Note that this updates a list of named event handlers.
4282 Calling this twice with two different event names assigns
4283 two different handlers, but calling it twice with the
4284 same event name assigns only one handler.
4286 @item @code{-variant} @var{name} -- specifies a variant of the target,
4287 which OpenOCD needs to know about.
4289 @item @code{-work-area-backup} (@option{0}|@option{1}) -- says
4290 whether the work area gets backed up; by default,
4291 @emph{it is not backed up.}
4292 When possible, use a working_area that doesn't need to be backed up,
4293 since performing a backup slows down operations.
4294 For example, the beginning of an SRAM block is likely to
4295 be used by most build systems, but the end is often unused.
4297 @item @code{-work-area-size} @var{size} -- specify work are size,
4298 in bytes. The same size applies regardless of whether its physical
4299 or virtual address is being used.
4301 @item @code{-work-area-phys} @var{address} -- set the work area
4302 base @var{address} to be used when no MMU is active.
4304 @item @code{-work-area-virt} @var{address} -- set the work area
4305 base @var{address} to be used when an MMU is active.
4306 @emph{Do not specify a value for this except on targets with an MMU.}
4307 The value should normally correspond to a static mapping for the
4308 @code{-work-area-phys} address, set up by the current operating system.
4310 @item @code{-rtos} @var{rtos_type} -- enable rtos support for target,
4311 @var{rtos_type} can be one of @option{auto}|@option{eCos}|@option{ThreadX}|
4312 @option{FreeRTOS}|@option{linux}|@option{ChibiOS}|@option{embKernel}.
4317 @section Other $target_name Commands
4318 @cindex object command
4320 The Tcl/Tk language has the concept of object commands,
4321 and OpenOCD adopts that same model for targets.
4323 A good Tk example is a on screen button.
4324 Once a button is created a button
4325 has a name (a path in Tk terms) and that name is useable as a first
4326 class command. For example in Tk, one can create a button and later
4327 configure it like this:
4331 button .foobar -background red -command @{ foo @}
4333 .foobar configure -foreground blue
4335 set x [.foobar cget -background]
4337 puts [format "The button is %s" $x]
4340 In OpenOCD's terms, the ``target'' is an object just like a Tcl/Tk
4341 button, and its object commands are invoked the same way.
4344 str912.cpu mww 0x1234 0x42
4345 omap3530.cpu mww 0x5555 123
4348 The commands supported by OpenOCD target objects are:
4350 @deffn Command {$target_name arp_examine}
4351 @deffnx Command {$target_name arp_halt}
4352 @deffnx Command {$target_name arp_poll}
4353 @deffnx Command {$target_name arp_reset}
4354 @deffnx Command {$target_name arp_waitstate}
4355 Internal OpenOCD scripts (most notably @file{startup.tcl})
4356 use these to deal with specific reset cases.
4357 They are not otherwise documented here.
4360 @deffn Command {$target_name array2mem} arrayname width address count
4361 @deffnx Command {$target_name mem2array} arrayname width address count
4362 These provide an efficient script-oriented interface to memory.
4363 The @code{array2mem} primitive writes bytes, halfwords, or words;
4364 while @code{mem2array} reads them.
4365 In both cases, the TCL side uses an array, and
4366 the target side uses raw memory.
4368 The efficiency comes from enabling the use of
4369 bulk JTAG data transfer operations.
4370 The script orientation comes from working with data
4371 values that are packaged for use by TCL scripts;
4372 @command{mdw} type primitives only print data they retrieve,
4373 and neither store nor return those values.
4376 @item @var{arrayname} ... is the name of an array variable
4377 @item @var{width} ... is 8/16/32 - indicating the memory access size
4378 @item @var{address} ... is the target memory address
4379 @item @var{count} ... is the number of elements to process
4383 @deffn Command {$target_name cget} queryparm
4384 Each configuration parameter accepted by
4385 @command{$target_name configure}
4386 can be individually queried, to return its current value.
4387 The @var{queryparm} is a parameter name
4388 accepted by that command, such as @code{-work-area-phys}.
4389 There are a few special cases:
4392 @item @code{-event} @var{event_name} -- returns the handler for the
4393 event named @var{event_name}.
4394 This is a special case because setting a handler requires
4396 @item @code{-type} -- returns the target type.
4397 This is a special case because this is set using
4398 @command{target create} and can't be changed
4399 using @command{$target_name configure}.
4402 For example, if you wanted to summarize information about
4403 all the targets you might use something like this:
4406 foreach name [target names] @{
4407 set y [$name cget -endian]
4408 set z [$name cget -type]
4409 puts [format "Chip %d is %s, Endian: %s, type: %s" \
4415 @anchor{targetcurstate}
4416 @deffn Command {$target_name curstate}
4417 Displays the current target state:
4418 @code{debug-running},
4421 @code{running}, or @code{unknown}.
4422 (Also, @pxref{eventpolling,,Event Polling}.)
4425 @deffn Command {$target_name eventlist}
4426 Displays a table listing all event handlers
4427 currently associated with this target.
4428 @xref{targetevents,,Target Events}.
4431 @deffn Command {$target_name invoke-event} event_name
4432 Invokes the handler for the event named @var{event_name}.
4433 (This is primarily intended for use by OpenOCD framework
4434 code, for example by the reset code in @file{startup.tcl}.)
4437 @deffn Command {$target_name mdw} addr [count]
4438 @deffnx Command {$target_name mdh} addr [count]
4439 @deffnx Command {$target_name mdb} addr [count]
4440 Display contents of address @var{addr}, as
4441 32-bit words (@command{mdw}), 16-bit halfwords (@command{mdh}),
4442 or 8-bit bytes (@command{mdb}).
4443 If @var{count} is specified, displays that many units.
4444 (If you want to manipulate the data instead of displaying it,
4445 see the @code{mem2array} primitives.)
4448 @deffn Command {$target_name mww} addr word
4449 @deffnx Command {$target_name mwh} addr halfword
4450 @deffnx Command {$target_name mwb} addr byte
4451 Writes the specified @var{word} (32 bits),
4452 @var{halfword} (16 bits), or @var{byte} (8-bit) pattern,
4453 at the specified address @var{addr}.
4456 @anchor{targetevents}
4457 @section Target Events
4458 @cindex target events
4460 At various times, certain things can happen, or you want them to happen.
4463 @item What should happen when GDB connects? Should your target reset?
4464 @item When GDB tries to flash the target, do you need to enable the flash via a special command?
4465 @item Is using SRST appropriate (and possible) on your system?
4466 Or instead of that, do you need to issue JTAG commands to trigger reset?
4467 SRST usually resets everything on the scan chain, which can be inappropriate.
4468 @item During reset, do you need to write to certain memory locations
4469 to set up system clocks or
4470 to reconfigure the SDRAM?
4471 How about configuring the watchdog timer, or other peripherals,
4472 to stop running while you hold the core stopped for debugging?
4475 All of the above items can be addressed by target event handlers.
4476 These are set up by @command{$target_name configure -event} or
4477 @command{target create ... -event}.
4479 The programmer's model matches the @code{-command} option used in Tcl/Tk
4480 buttons and events. The two examples below act the same, but one creates
4481 and invokes a small procedure while the other inlines it.
4484 proc my_attach_proc @{ @} @{
4488 mychip.cpu configure -event gdb-attach my_attach_proc
4489 mychip.cpu configure -event gdb-attach @{
4491 # To make flash probe and gdb load to flash work we need a reset init.
4496 The following target events are defined:
4499 @item @b{debug-halted}
4500 @* The target has halted for debug reasons (i.e.: breakpoint)
4501 @item @b{debug-resumed}
4502 @* The target has resumed (i.e.: gdb said run)
4503 @item @b{early-halted}
4504 @* Occurs early in the halt process
4505 @item @b{examine-start}
4506 @* Before target examine is called.
4507 @item @b{examine-end}
4508 @* After target examine is called with no errors.
4509 @item @b{gdb-attach}
4510 @* When GDB connects. This is before any communication with the target, so this
4511 can be used to set up the target so it is possible to probe flash. Probing flash
4512 is necessary during gdb connect if gdb load is to write the image to flash. Another
4513 use of the flash memory map is for GDB to automatically hardware/software breakpoints
4514 depending on whether the breakpoint is in RAM or read only memory.
4515 @item @b{gdb-detach}
4516 @* When GDB disconnects
4518 @* When the target has halted and GDB is not doing anything (see early halt)
4519 @item @b{gdb-flash-erase-start}
4520 @* Before the GDB flash process tries to erase the flash
4521 @item @b{gdb-flash-erase-end}
4522 @* After the GDB flash process has finished erasing the flash
4523 @item @b{gdb-flash-write-start}
4524 @* Before GDB writes to the flash
4525 @item @b{gdb-flash-write-end}
4526 @* After GDB writes to the flash
4528 @* Before the target steps, gdb is trying to start/resume the target
4530 @* The target has halted
4531 @item @b{reset-assert-pre}
4532 @* Issued as part of @command{reset} processing
4533 after @command{reset_init} was triggered
4534 but before either SRST alone is re-asserted on the scan chain,
4535 or @code{reset-assert} is triggered.
4536 @item @b{reset-assert}
4537 @* Issued as part of @command{reset} processing
4538 after @command{reset-assert-pre} was triggered.
4539 When such a handler is present, cores which support this event will use
4540 it instead of asserting SRST.
4541 This support is essential for debugging with JTAG interfaces which
4542 don't include an SRST line (JTAG doesn't require SRST), and for
4543 selective reset on scan chains that have multiple targets.
4544 @item @b{reset-assert-post}
4545 @* Issued as part of @command{reset} processing
4546 after @code{reset-assert} has been triggered.
4547 or the target asserted SRST on the entire scan chain.
4548 @item @b{reset-deassert-pre}
4549 @* Issued as part of @command{reset} processing
4550 after @code{reset-assert-post} has been triggered.
4551 @item @b{reset-deassert-post}
4552 @* Issued as part of @command{reset} processing
4553 after @code{reset-deassert-pre} has been triggered
4554 and (if the target is using it) after SRST has been
4555 released on the scan chain.
4557 @* Issued as the final step in @command{reset} processing.
4559 @item @b{reset-halt-post}
4560 @* Currently not used
4561 @item @b{reset-halt-pre}
4562 @* Currently not used
4564 @item @b{reset-init}
4565 @* Used by @b{reset init} command for board-specific initialization.
4566 This event fires after @emph{reset-deassert-post}.
4568 This is where you would configure PLLs and clocking, set up DRAM so
4569 you can download programs that don't fit in on-chip SRAM, set up pin
4570 multiplexing, and so on.
4571 (You may be able to switch to a fast JTAG clock rate here, after
4572 the target clocks are fully set up.)
4573 @item @b{reset-start}
4574 @* Issued as part of @command{reset} processing
4575 before @command{reset_init} is called.
4577 This is the most robust place to use @command{jtag_rclk}
4578 or @command{adapter_khz} to switch to a low JTAG clock rate,
4579 when reset disables PLLs needed to use a fast clock.
4581 @item @b{reset-wait-pos}
4582 @* Currently not used
4583 @item @b{reset-wait-pre}
4584 @* Currently not used
4586 @item @b{resume-start}
4587 @* Before any target is resumed
4588 @item @b{resume-end}
4589 @* After all targets have resumed
4591 @* Target has resumed
4594 @node Flash Commands
4595 @chapter Flash Commands
4597 OpenOCD has different commands for NOR and NAND flash;
4598 the ``flash'' command works with NOR flash, while
4599 the ``nand'' command works with NAND flash.
4600 This partially reflects different hardware technologies:
4601 NOR flash usually supports direct CPU instruction and data bus access,
4602 while data from a NAND flash must be copied to memory before it can be
4603 used. (SPI flash must also be copied to memory before use.)
4604 However, the documentation also uses ``flash'' as a generic term;
4605 for example, ``Put flash configuration in board-specific files''.
4609 @item Configure via the command @command{flash bank}
4610 @* Do this in a board-specific configuration file,
4611 passing parameters as needed by the driver.
4612 @item Operate on the flash via @command{flash subcommand}
4613 @* Often commands to manipulate the flash are typed by a human, or run
4614 via a script in some automated way. Common tasks include writing a
4615 boot loader, operating system, or other data.
4617 @* Flashing via GDB requires the flash be configured via ``flash
4618 bank'', and the GDB flash features be enabled.
4619 @xref{gdbconfiguration,,GDB Configuration}.
4622 Many CPUs have the ablity to ``boot'' from the first flash bank.
4623 This means that misprogramming that bank can ``brick'' a system,
4624 so that it can't boot.
4625 JTAG tools, like OpenOCD, are often then used to ``de-brick'' the
4626 board by (re)installing working boot firmware.
4628 @anchor{norconfiguration}
4629 @section Flash Configuration Commands
4630 @cindex flash configuration
4632 @deffn {Config Command} {flash bank} name driver base size chip_width bus_width target [driver_options]
4633 Configures a flash bank which provides persistent storage
4634 for addresses from @math{base} to @math{base + size - 1}.
4635 These banks will often be visible to GDB through the target's memory map.
4636 In some cases, configuring a flash bank will activate extra commands;
4637 see the driver-specific documentation.
4640 @item @var{name} ... may be used to reference the flash bank
4641 in other flash commands. A number is also available.
4642 @item @var{driver} ... identifies the controller driver
4643 associated with the flash bank being declared.
4644 This is usually @code{cfi} for external flash, or else
4645 the name of a microcontroller with embedded flash memory.
4646 @xref{flashdriverlist,,Flash Driver List}.
4647 @item @var{base} ... Base address of the flash chip.
4648 @item @var{size} ... Size of the chip, in bytes.
4649 For some drivers, this value is detected from the hardware.
4650 @item @var{chip_width} ... Width of the flash chip, in bytes;
4651 ignored for most microcontroller drivers.
4652 @item @var{bus_width} ... Width of the data bus used to access the
4653 chip, in bytes; ignored for most microcontroller drivers.
4654 @item @var{target} ... Names the target used to issue
4655 commands to the flash controller.
4656 @comment Actually, it's currently a controller-specific parameter...
4657 @item @var{driver_options} ... drivers may support, or require,
4658 additional parameters. See the driver-specific documentation
4659 for more information.
4662 This command is not available after OpenOCD initialization has completed.
4663 Use it in board specific configuration files, not interactively.
4667 @comment the REAL name for this command is "ocd_flash_banks"
4668 @comment less confusing would be: "flash list" (like "nand list")
4669 @deffn Command {flash banks}
4670 Prints a one-line summary of each device that was
4671 declared using @command{flash bank}, numbered from zero.
4672 Note that this is the @emph{plural} form;
4673 the @emph{singular} form is a very different command.
4676 @deffn Command {flash list}
4677 Retrieves a list of associative arrays for each device that was
4678 declared using @command{flash bank}, numbered from zero.
4679 This returned list can be manipulated easily from within scripts.
4682 @deffn Command {flash probe} num
4683 Identify the flash, or validate the parameters of the configured flash. Operation
4684 depends on the flash type.
4685 The @var{num} parameter is a value shown by @command{flash banks}.
4686 Most flash commands will implicitly @emph{autoprobe} the bank;
4687 flash drivers can distinguish between probing and autoprobing,
4688 but most don't bother.
4691 @section Erasing, Reading, Writing to Flash
4692 @cindex flash erasing
4693 @cindex flash reading
4694 @cindex flash writing
4695 @cindex flash programming
4696 @anchor{flashprogrammingcommands}
4698 One feature distinguishing NOR flash from NAND or serial flash technologies
4699 is that for read access, it acts exactly like any other addressible memory.
4700 This means you can use normal memory read commands like @command{mdw} or
4701 @command{dump_image} with it, with no special @command{flash} subcommands.
4702 @xref{memoryaccess,,Memory access}, and @ref{imageaccess,,Image access}.
4704 Write access works differently. Flash memory normally needs to be erased
4705 before it's written. Erasing a sector turns all of its bits to ones, and
4706 writing can turn ones into zeroes. This is why there are special commands
4707 for interactive erasing and writing, and why GDB needs to know which parts
4708 of the address space hold NOR flash memory.
4711 Most of these erase and write commands leverage the fact that NOR flash
4712 chips consume target address space. They implicitly refer to the current
4713 JTAG target, and map from an address in that target's address space
4714 back to a flash bank.
4715 @comment In May 2009, those mappings may fail if any bank associated
4716 @comment with that target doesn't succesfuly autoprobe ... bug worth fixing?
4717 A few commands use abstract addressing based on bank and sector numbers,
4718 and don't depend on searching the current target and its address space.
4719 Avoid confusing the two command models.
4722 Some flash chips implement software protection against accidental writes,
4723 since such buggy writes could in some cases ``brick'' a system.
4724 For such systems, erasing and writing may require sector protection to be
4726 Examples include CFI flash such as ``Intel Advanced Bootblock flash'',
4727 and AT91SAM7 on-chip flash.
4728 @xref{flashprotect,,flash protect}.
4730 @deffn Command {flash erase_sector} num first last
4731 Erase sectors in bank @var{num}, starting at sector @var{first}
4732 up to and including @var{last}.
4733 Sector numbering starts at 0.
4734 Providing a @var{last} sector of @option{last}
4735 specifies "to the end of the flash bank".
4736 The @var{num} parameter is a value shown by @command{flash banks}.
4739 @deffn Command {flash erase_address} [@option{pad}] [@option{unlock}] address length
4740 Erase sectors starting at @var{address} for @var{length} bytes.
4741 Unless @option{pad} is specified, @math{address} must begin a
4742 flash sector, and @math{address + length - 1} must end a sector.
4743 Specifying @option{pad} erases extra data at the beginning and/or
4744 end of the specified region, as needed to erase only full sectors.
4745 The flash bank to use is inferred from the @var{address}, and
4746 the specified length must stay within that bank.
4747 As a special case, when @var{length} is zero and @var{address} is
4748 the start of the bank, the whole flash is erased.
4749 If @option{unlock} is specified, then the flash is unprotected
4750 before erase starts.
4753 @deffn Command {flash fillw} address word length
4754 @deffnx Command {flash fillh} address halfword length
4755 @deffnx Command {flash fillb} address byte length
4756 Fills flash memory with the specified @var{word} (32 bits),
4757 @var{halfword} (16 bits), or @var{byte} (8-bit) pattern,
4758 starting at @var{address} and continuing
4759 for @var{length} units (word/halfword/byte).
4760 No erasure is done before writing; when needed, that must be done
4761 before issuing this command.
4762 Writes are done in blocks of up to 1024 bytes, and each write is
4763 verified by reading back the data and comparing it to what was written.
4764 The flash bank to use is inferred from the @var{address} of
4765 each block, and the specified length must stay within that bank.
4767 @comment no current checks for errors if fill blocks touch multiple banks!
4769 @deffn Command {flash write_bank} num filename offset
4770 Write the binary @file{filename} to flash bank @var{num},
4771 starting at @var{offset} bytes from the beginning of the bank.
4772 The @var{num} parameter is a value shown by @command{flash banks}.
4775 @deffn Command {flash write_image} [erase] [unlock] filename [offset] [type]
4776 Write the image @file{filename} to the current target's flash bank(s).
4777 A relocation @var{offset} may be specified, in which case it is added
4778 to the base address for each section in the image.
4779 The file [@var{type}] can be specified
4780 explicitly as @option{bin} (binary), @option{ihex} (Intel hex),
4781 @option{elf} (ELF file), @option{s19} (Motorola s19).
4782 @option{mem}, or @option{builder}.
4783 The relevant flash sectors will be erased prior to programming
4784 if the @option{erase} parameter is given. If @option{unlock} is
4785 provided, then the flash banks are unlocked before erase and
4786 program. The flash bank to use is inferred from the address of
4790 Be careful using the @option{erase} flag when the flash is holding
4791 data you want to preserve.
4792 Portions of the flash outside those described in the image's
4793 sections might be erased with no notice.
4796 When a section of the image being written does not fill out all the
4797 sectors it uses, the unwritten parts of those sectors are necessarily
4798 also erased, because sectors can't be partially erased.
4800 Data stored in sector "holes" between image sections are also affected.
4801 For example, "@command{flash write_image erase ...}" of an image with
4802 one byte at the beginning of a flash bank and one byte at the end
4803 erases the entire bank -- not just the two sectors being written.
4805 Also, when flash protection is important, you must re-apply it after
4806 it has been removed by the @option{unlock} flag.
4811 @section Other Flash commands
4812 @cindex flash protection
4814 @deffn Command {flash erase_check} num
4815 Check erase state of sectors in flash bank @var{num},
4816 and display that status.
4817 The @var{num} parameter is a value shown by @command{flash banks}.
4820 @deffn Command {flash info} num
4821 Print info about flash bank @var{num}
4822 The @var{num} parameter is a value shown by @command{flash banks}.
4823 This command will first query the hardware, it does not print cached
4824 and possibly stale information.
4827 @anchor{flashprotect}
4828 @deffn Command {flash protect} num first last (@option{on}|@option{off})
4829 Enable (@option{on}) or disable (@option{off}) protection of flash sectors
4830 in flash bank @var{num}, starting at sector @var{first}
4831 and continuing up to and including @var{last}.
4832 Providing a @var{last} sector of @option{last}
4833 specifies "to the end of the flash bank".
4834 The @var{num} parameter is a value shown by @command{flash banks}.
4838 @deffn Command {program} filename [verify] [reset] [offset]
4839 This is a helper script that simplifies using OpenOCD as a standalone
4840 programmer. The only required parameter is @option{filename}, the others are optional.
4841 @xref{Flash Programming}.
4844 @anchor{flashdriverlist}
4845 @section Flash Driver List
4846 As noted above, the @command{flash bank} command requires a driver name,
4847 and allows driver-specific options and behaviors.
4848 Some drivers also activate driver-specific commands.
4850 @subsection External Flash
4852 @deffn {Flash Driver} cfi
4853 @cindex Common Flash Interface
4855 The ``Common Flash Interface'' (CFI) is the main standard for
4856 external NOR flash chips, each of which connects to a
4857 specific external chip select on the CPU.
4858 Frequently the first such chip is used to boot the system.
4859 Your board's @code{reset-init} handler might need to
4860 configure additional chip selects using other commands (like: @command{mww} to
4861 configure a bus and its timings), or
4862 perhaps configure a GPIO pin that controls the ``write protect'' pin
4864 The CFI driver can use a target-specific working area to significantly
4867 The CFI driver can accept the following optional parameters, in any order:
4870 @item @var{jedec_probe} ... is used to detect certain non-CFI flash ROMs,
4871 like AM29LV010 and similar types.
4872 @item @var{x16_as_x8} ... when a 16-bit flash is hooked up to an 8-bit bus.
4875 To configure two adjacent banks of 16 MBytes each, both sixteen bits (two bytes)
4876 wide on a sixteen bit bus:
4879 flash bank $_FLASHNAME cfi 0x00000000 0x01000000 2 2 $_TARGETNAME
4880 flash bank $_FLASHNAME cfi 0x01000000 0x01000000 2 2 $_TARGETNAME
4883 To configure one bank of 32 MBytes
4884 built from two sixteen bit (two byte) wide parts wired in parallel
4885 to create a thirty-two bit (four byte) bus with doubled throughput:
4888 flash bank $_FLASHNAME cfi 0x00000000 0x02000000 2 4 $_TARGETNAME
4891 @c "cfi part_id" disabled
4894 @deffn {Flash Driver} lpcspifi
4895 @cindex NXP SPI Flash Interface
4898 NXP's LPC43xx and LPC18xx families include a proprietary SPI
4899 Flash Interface (SPIFI) peripheral that can drive and provide
4900 memory mapped access to external SPI flash devices.
4902 The lpcspifi driver initializes this interface and provides
4903 program and erase functionality for these serial flash devices.
4904 Use of this driver @b{requires} a working area of at least 1kB
4905 to be configured on the target device; more than this will
4906 significantly reduce flash programming times.
4908 The setup command only requires the @var{base} parameter. All
4909 other parameters are ignored, and the flash size and layout
4910 are configured by the driver.
4913 flash bank $_FLASHNAME lpcspifi 0x14000000 0 0 0 $_TARGETNAME
4918 @deffn {Flash Driver} stmsmi
4919 @cindex STMicroelectronics Serial Memory Interface
4922 Some devices form STMicroelectronics (e.g. STR75x MCU family,
4923 SPEAr MPU family) include a proprietary
4924 ``Serial Memory Interface'' (SMI) controller able to drive external
4926 Depending on specific device and board configuration, up to 4 external
4927 flash devices can be connected.
4929 SMI makes the flash content directly accessible in the CPU address
4930 space; each external device is mapped in a memory bank.
4931 CPU can directly read data, execute code and boot from SMI banks.
4932 Normal OpenOCD commands like @command{mdw} can be used to display
4935 The setup command only requires the @var{base} parameter in order
4936 to identify the memory bank.
4937 All other parameters are ignored. Additional information, like
4938 flash size, are detected automatically.
4941 flash bank $_FLASHNAME stmsmi 0xf8000000 0 0 0 $_TARGETNAME
4946 @subsection Internal Flash (Microcontrollers)
4948 @deffn {Flash Driver} aduc702x
4949 The ADUC702x analog microcontrollers from Analog Devices
4950 include internal flash and use ARM7TDMI cores.
4951 The aduc702x flash driver works with models ADUC7019 through ADUC7028.
4952 The setup command only requires the @var{target} argument
4953 since all devices in this family have the same memory layout.
4956 flash bank $_FLASHNAME aduc702x 0 0 0 0 $_TARGETNAME
4961 @deffn {Flash Driver} at91sam3
4963 All members of the AT91SAM3 microcontroller family from
4964 Atmel include internal flash and use ARM's Cortex-M3 core. The driver
4965 currently (6/22/09) recognizes the AT91SAM3U[1/2/4][C/E] chips. Note
4966 that the driver was orginaly developed and tested using the
4967 AT91SAM3U4E, using a SAM3U-EK eval board. Support for other chips in
4968 the family was cribbed from the data sheet. @emph{Note to future
4969 readers/updaters: Please remove this worrysome comment after other
4970 chips are confirmed.}
4972 The AT91SAM3U4[E/C] (256K) chips have two flash banks; most other chips
4973 have one flash bank. In all cases the flash banks are at
4974 the following fixed locations:
4977 # Flash bank 0 - all chips
4978 flash bank $_FLASHNAME at91sam3 0x00080000 0 1 1 $_TARGETNAME
4979 # Flash bank 1 - only 256K chips
4980 flash bank $_FLASHNAME at91sam3 0x00100000 0 1 1 $_TARGETNAME
4983 Internally, the AT91SAM3 flash memory is organized as follows.
4984 Unlike the AT91SAM7 chips, these are not used as parameters
4985 to the @command{flash bank} command:
4988 @item @emph{N-Banks:} 256K chips have 2 banks, others have 1 bank.
4989 @item @emph{Bank Size:} 128K/64K Per flash bank
4990 @item @emph{Sectors:} 16 or 8 per bank
4991 @item @emph{SectorSize:} 8K Per Sector
4992 @item @emph{PageSize:} 256 bytes per page. Note that OpenOCD operates on 'sector' sizes, not page sizes.
4995 The AT91SAM3 driver adds some additional commands:
4997 @deffn Command {at91sam3 gpnvm}
4998 @deffnx Command {at91sam3 gpnvm clear} number
4999 @deffnx Command {at91sam3 gpnvm set} number
5000 @deffnx Command {at91sam3 gpnvm show} [@option{all}|number]
5001 With no parameters, @command{show} or @command{show all},
5002 shows the status of all GPNVM bits.
5003 With @command{show} @var{number}, displays that bit.
5005 With @command{set} @var{number} or @command{clear} @var{number},
5006 modifies that GPNVM bit.
5009 @deffn Command {at91sam3 info}
5010 This command attempts to display information about the AT91SAM3
5011 chip. @emph{First} it read the @code{CHIPID_CIDR} [address 0x400e0740, see
5012 Section 28.2.1, page 505 of the AT91SAM3U 29/may/2009 datasheet,
5013 document id: doc6430A] and decodes the values. @emph{Second} it reads the
5014 various clock configuration registers and attempts to display how it
5015 believes the chip is configured. By default, the SLOWCLK is assumed to
5016 be 32768 Hz, see the command @command{at91sam3 slowclk}.
5019 @deffn Command {at91sam3 slowclk} [value]
5020 This command shows/sets the slow clock frequency used in the
5021 @command{at91sam3 info} command calculations above.
5025 @deffn {Flash Driver} at91sam4
5027 All members of the AT91SAM4 microcontroller family from
5028 Atmel include internal flash and use ARM's Cortex-M4 core.
5029 This driver uses the same cmd names/syntax as @xref{at91sam3}.
5032 @deffn {Flash Driver} at91sam7
5033 All members of the AT91SAM7 microcontroller family from Atmel include
5034 internal flash and use ARM7TDMI cores. The driver automatically
5035 recognizes a number of these chips using the chip identification
5036 register, and autoconfigures itself.
5039 flash bank $_FLASHNAME at91sam7 0 0 0 0 $_TARGETNAME
5042 For chips which are not recognized by the controller driver, you must
5043 provide additional parameters in the following order:
5046 @item @var{chip_model} ... label used with @command{flash info}
5048 @item @var{sectors_per_bank}
5049 @item @var{pages_per_sector}
5050 @item @var{pages_size}
5051 @item @var{num_nvm_bits}
5052 @item @var{freq_khz} ... required if an external clock is provided,
5053 optional (but recommended) when the oscillator frequency is known
5056 It is recommended that you provide zeroes for all of those values
5057 except the clock frequency, so that everything except that frequency
5058 will be autoconfigured.
5059 Knowing the frequency helps ensure correct timings for flash access.
5061 The flash controller handles erases automatically on a page (128/256 byte)
5062 basis, so explicit erase commands are not necessary for flash programming.
5063 However, there is an ``EraseAll`` command that can erase an entire flash
5064 plane (of up to 256KB), and it will be used automatically when you issue
5065 @command{flash erase_sector} or @command{flash erase_address} commands.
5067 @deffn Command {at91sam7 gpnvm} bitnum (@option{set}|@option{clear})
5068 Set or clear a ``General Purpose Non-Volatile Memory'' (GPNVM)
5069 bit for the processor. Each processor has a number of such bits,
5070 used for controlling features such as brownout detection (so they
5071 are not truly general purpose).
5073 This assumes that the first flash bank (number 0) is associated with
5074 the appropriate at91sam7 target.
5079 @deffn {Flash Driver} avr
5080 The AVR 8-bit microcontrollers from Atmel integrate flash memory.
5081 @emph{The current implementation is incomplete.}
5082 @comment - defines mass_erase ... pointless given flash_erase_address
5085 @deffn {Flash Driver} efm32
5086 All members of the EFM32 microcontroller family from Energy Micro include
5087 internal flash and use ARM Cortex M3 cores. The driver automatically recognizes
5088 a number of these chips using the chip identification register, and
5089 autoconfigures itself.
5091 flash bank $_FLASHNAME efm32 0 0 0 0 $_TARGETNAME
5093 @emph{The current implementation is incomplete. Unprotecting flash pages is not
5097 @deffn {Flash Driver} lpc2000
5098 Most members of the LPC1700, LPC1800, LPC2000 and LPC4300 microcontroller
5099 families from NXP include internal flash and use Cortex-M3 (LPC1700, LPC1800),
5100 Cortex-M4 (LPC4300) or ARM7TDMI (LPC2000) cores.
5103 There are LPC2000 devices which are not supported by the @var{lpc2000}
5105 The LPC2888 is supported by the @var{lpc288x} driver.
5106 The LPC29xx family is supported by the @var{lpc2900} driver.
5109 The @var{lpc2000} driver defines two mandatory and one optional parameters,
5110 which must appear in the following order:
5113 @item @var{variant} ... required, may be
5114 @option{lpc2000_v1} (older LPC21xx and LPC22xx)
5115 @option{lpc2000_v2} (LPC213x, LPC214x, LPC210[123], LPC23xx and LPC24xx)
5116 @option{lpc1700} (LPC175x and LPC176x)
5117 or @option{lpc4300} - available also as @option{lpc1800} alias (LPC18x[2357] and
5119 @item @var{clock_kHz} ... the frequency, in kiloHertz,
5120 at which the core is running
5121 @item @option{calc_checksum} ... optional (but you probably want to provide this!),
5122 telling the driver to calculate a valid checksum for the exception vector table.
5124 If you don't provide @option{calc_checksum} when you're writing the vector
5125 table, the boot ROM will almost certainly ignore your flash image.
5126 However, if you do provide it,
5127 with most tool chains @command{verify_image} will fail.
5131 LPC flashes don't require the chip and bus width to be specified.
5134 flash bank $_FLASHNAME lpc2000 0x0 0x7d000 0 0 $_TARGETNAME \
5135 lpc2000_v2 14765 calc_checksum
5138 @deffn {Command} {lpc2000 part_id} bank
5139 Displays the four byte part identifier associated with
5140 the specified flash @var{bank}.
5144 @deffn {Flash Driver} lpc288x
5145 The LPC2888 microcontroller from NXP needs slightly different flash
5146 support from its lpc2000 siblings.
5147 The @var{lpc288x} driver defines one mandatory parameter,
5148 the programming clock rate in Hz.
5149 LPC flashes don't require the chip and bus width to be specified.
5152 flash bank $_FLASHNAME lpc288x 0 0 0 0 $_TARGETNAME 12000000
5156 @deffn {Flash Driver} lpc2900
5157 This driver supports the LPC29xx ARM968E based microcontroller family
5160 The predefined parameters @var{base}, @var{size}, @var{chip_width} and
5161 @var{bus_width} of the @code{flash bank} command are ignored. Flash size and
5162 sector layout are auto-configured by the driver.
5163 The driver has one additional mandatory parameter: The CPU clock rate
5164 (in kHz) at the time the flash operations will take place. Most of the time this
5165 will not be the crystal frequency, but a higher PLL frequency. The
5166 @code{reset-init} event handler in the board script is usually the place where
5169 The driver rejects flashless devices (currently the LPC2930).
5171 The EEPROM in LPC2900 devices is not mapped directly into the address space.
5172 It must be handled much more like NAND flash memory, and will therefore be
5173 handled by a separate @code{lpc2900_eeprom} driver (not yet available).
5175 Sector protection in terms of the LPC2900 is handled transparently. Every time a
5176 sector needs to be erased or programmed, it is automatically unprotected.
5177 What is shown as protection status in the @code{flash info} command, is
5178 actually the LPC2900 @emph{sector security}. This is a mechanism to prevent a
5179 sector from ever being erased or programmed again. As this is an irreversible
5180 mechanism, it is handled by a special command (@code{lpc2900 secure_sector}),
5181 and not by the standard @code{flash protect} command.
5183 Example for a 125 MHz clock frequency:
5185 flash bank $_FLASHNAME lpc2900 0 0 0 0 $_TARGETNAME 125000
5188 Some @code{lpc2900}-specific commands are defined. In the following command list,
5189 the @var{bank} parameter is the bank number as obtained by the
5190 @code{flash banks} command.
5192 @deffn Command {lpc2900 signature} bank
5193 Calculates a 128-bit hash value, the @emph{signature}, from the whole flash
5194 content. This is a hardware feature of the flash block, hence the calculation is
5195 very fast. You may use this to verify the content of a programmed device against
5200 signature: 0x5f40cdc8:0xc64e592e:0x10490f89:0x32a0f317
5204 @deffn Command {lpc2900 read_custom} bank filename
5205 Reads the 912 bytes of customer information from the flash index sector, and
5206 saves it to a file in binary format.
5209 lpc2900 read_custom 0 /path_to/customer_info.bin
5213 The index sector of the flash is a @emph{write-only} sector. It cannot be
5214 erased! In order to guard against unintentional write access, all following
5215 commands need to be preceeded by a successful call to the @code{password}
5218 @deffn Command {lpc2900 password} bank password
5219 You need to use this command right before each of the following commands:
5220 @code{lpc2900 write_custom}, @code{lpc2900 secure_sector},
5221 @code{lpc2900 secure_jtag}.
5223 The password string is fixed to "I_know_what_I_am_doing".
5226 lpc2900 password 0 I_know_what_I_am_doing
5227 Potentially dangerous operation allowed in next command!
5231 @deffn Command {lpc2900 write_custom} bank filename type
5232 Writes the content of the file into the customer info space of the flash index
5233 sector. The filetype can be specified with the @var{type} field. Possible values
5234 for @var{type} are: @var{bin} (binary), @var{ihex} (Intel hex format),
5235 @var{elf} (ELF binary) or @var{s19} (Motorola S-records). The file must
5236 contain a single section, and the contained data length must be exactly
5238 @quotation Attention
5239 This cannot be reverted! Be careful!
5243 lpc2900 write_custom 0 /path_to/customer_info.bin bin
5247 @deffn Command {lpc2900 secure_sector} bank first last
5248 Secures the sector range from @var{first} to @var{last} (including) against
5249 further program and erase operations. The sector security will be effective
5250 after the next power cycle.
5251 @quotation Attention
5252 This cannot be reverted! Be careful!
5254 Secured sectors appear as @emph{protected} in the @code{flash info} command.
5257 lpc2900 secure_sector 0 1 1
5259 #0 : lpc2900 at 0x20000000, size 0x000c0000, (...)
5260 # 0: 0x00000000 (0x2000 8kB) not protected
5261 # 1: 0x00002000 (0x2000 8kB) protected
5262 # 2: 0x00004000 (0x2000 8kB) not protected
5266 @deffn Command {lpc2900 secure_jtag} bank
5267 Irreversibly disable the JTAG port. The new JTAG security setting will be
5268 effective after the next power cycle.
5269 @quotation Attention
5270 This cannot be reverted! Be careful!
5274 lpc2900 secure_jtag 0
5279 @deffn {Flash Driver} ocl
5280 @emph{No idea what this is, other than using some arm7/arm9 core.}
5283 flash bank $_FLASHNAME ocl 0 0 0 0 $_TARGETNAME
5287 @deffn {Flash Driver} pic32mx
5288 The PIC32MX microcontrollers are based on the MIPS 4K cores,
5289 and integrate flash memory.
5292 flash bank $_FLASHNAME pix32mx 0x1fc00000 0 0 0 $_TARGETNAME
5293 flash bank $_FLASHNAME pix32mx 0x1d000000 0 0 0 $_TARGETNAME
5296 @comment numerous *disabled* commands are defined:
5297 @comment - chip_erase ... pointless given flash_erase_address
5298 @comment - lock, unlock ... pointless given protect on/off (yes?)
5299 @comment - pgm_word ... shouldn't bank be deduced from address??
5300 Some pic32mx-specific commands are defined:
5301 @deffn Command {pic32mx pgm_word} address value bank
5302 Programs the specified 32-bit @var{value} at the given @var{address}
5303 in the specified chip @var{bank}.
5305 @deffn Command {pic32mx unlock} bank
5306 Unlock and erase specified chip @var{bank}.
5307 This will remove any Code Protection.
5311 @deffn {Flash Driver} stellaris
5312 All members of the Stellaris LM3Sxxx microcontroller family from
5314 include internal flash and use ARM Cortex M3 cores.
5315 The driver automatically recognizes a number of these chips using
5316 the chip identification register, and autoconfigures itself.
5317 @footnote{Currently there is a @command{stellaris mass_erase} command.
5318 That seems pointless since the same effect can be had using the
5319 standard @command{flash erase_address} command.}
5322 flash bank $_FLASHNAME stellaris 0 0 0 0 $_TARGETNAME
5325 @deffn Command {stellaris recover bank_id}
5326 Performs the @emph{Recovering a "Locked" Device} procedure to
5327 restore the flash specified by @var{bank_id} and its associated
5328 nonvolatile registers to their factory default values (erased).
5329 This is the only way to remove flash protection or re-enable
5330 debugging if that capability has been disabled.
5332 Note that the final "power cycle the chip" step in this procedure
5333 must be performed by hand, since OpenOCD can't do it.
5335 if more than one Stellaris chip is connected, the procedure is
5336 applied to all of them.
5341 @deffn {Flash Driver} stm32f1x
5342 All members of the STM32F0, STM32F1 and STM32F3 microcontroller families
5343 from ST Microelectronics include internal flash and use ARM Cortex-M0/M3/M4 cores.
5344 The driver automatically recognizes a number of these chips using
5345 the chip identification register, and autoconfigures itself.
5348 flash bank $_FLASHNAME stm32f1x 0 0 0 0 $_TARGETNAME
5351 Note that some devices have been found that have a flash size register that contains
5352 an invalid value, to workaround this issue you can override the probed value used by
5356 flash bank $_FLASHNAME stm32f1x 0 0x20000 0 0 $_TARGETNAME
5359 If you have a target with dual flash banks then define the second bank
5360 as per the following example.
5362 flash bank $_FLASHNAME stm32f1x 0x08080000 0 0 0 $_TARGETNAME
5365 Some stm32f1x-specific commands
5366 @footnote{Currently there is a @command{stm32f1x mass_erase} command.
5367 That seems pointless since the same effect can be had using the
5368 standard @command{flash erase_address} command.}
5371 @deffn Command {stm32f1x lock} num
5372 Locks the entire stm32 device.
5373 The @var{num} parameter is a value shown by @command{flash banks}.
5376 @deffn Command {stm32f1x unlock} num
5377 Unlocks the entire stm32 device.
5378 The @var{num} parameter is a value shown by @command{flash banks}.
5381 @deffn Command {stm32f1x options_read} num
5382 Read and display the stm32 option bytes written by
5383 the @command{stm32f1x options_write} command.
5384 The @var{num} parameter is a value shown by @command{flash banks}.
5387 @deffn Command {stm32f1x options_write} num (@option{SWWDG}|@option{HWWDG}) (@option{RSTSTNDBY}|@option{NORSTSTNDBY}) (@option{RSTSTOP}|@option{NORSTSTOP})
5388 Writes the stm32 option byte with the specified values.
5389 The @var{num} parameter is a value shown by @command{flash banks}.
5393 @deffn {Flash Driver} stm32f2x
5394 All members of the STM32F2 and STM32F4 microcontroller families from ST Microelectronics
5395 include internal flash and use ARM Cortex-M3/M4 cores.
5396 The driver automatically recognizes a number of these chips using
5397 the chip identification register, and autoconfigures itself.
5399 Note that some devices have been found that have a flash size register that contains
5400 an invalid value, to workaround this issue you can override the probed value used by
5404 flash bank $_FLASHNAME stm32f2x 0 0x20000 0 0 $_TARGETNAME
5407 Some stm32f2x-specific commands are defined:
5409 @deffn Command {stm32f2x lock} num
5410 Locks the entire stm32 device.
5411 The @var{num} parameter is a value shown by @command{flash banks}.
5414 @deffn Command {stm32f2x unlock} num
5415 Unlocks the entire stm32 device.
5416 The @var{num} parameter is a value shown by @command{flash banks}.
5420 @deffn {Flash Driver} stm32lx
5421 All members of the STM32L microcontroller families from ST Microelectronics
5422 include internal flash and use ARM Cortex-M3 cores.
5423 The driver automatically recognizes a number of these chips using
5424 the chip identification register, and autoconfigures itself.
5426 Note that some devices have been found that have a flash size register that contains
5427 an invalid value, to workaround this issue you can override the probed value used by
5431 flash bank $_FLASHNAME stm32lx 0 0x20000 0 0 $_TARGETNAME
5435 @deffn {Flash Driver} str7x
5436 All members of the STR7 microcontroller family from ST Microelectronics
5437 include internal flash and use ARM7TDMI cores.
5438 The @var{str7x} driver defines one mandatory parameter, @var{variant},
5439 which is either @code{STR71x}, @code{STR73x} or @code{STR75x}.
5442 flash bank $_FLASHNAME str7x 0x40000000 0x00040000 0 0 $_TARGETNAME STR71x
5445 @deffn Command {str7x disable_jtag} bank
5446 Activate the Debug/Readout protection mechanism
5447 for the specified flash bank.
5451 @deffn {Flash Driver} str9x
5452 Most members of the STR9 microcontroller family from ST Microelectronics
5453 include internal flash and use ARM966E cores.
5454 The str9 needs the flash controller to be configured using
5455 the @command{str9x flash_config} command prior to Flash programming.
5458 flash bank $_FLASHNAME str9x 0x40000000 0x00040000 0 0 $_TARGETNAME
5459 str9x flash_config 0 4 2 0 0x80000
5462 @deffn Command {str9x flash_config} num bbsr nbbsr bbadr nbbadr
5463 Configures the str9 flash controller.
5464 The @var{num} parameter is a value shown by @command{flash banks}.
5467 @item @var{bbsr} - Boot Bank Size register
5468 @item @var{nbbsr} - Non Boot Bank Size register
5469 @item @var{bbadr} - Boot Bank Start Address register
5470 @item @var{nbbadr} - Boot Bank Start Address register
5476 @deffn {Flash Driver} tms470
5477 Most members of the TMS470 microcontroller family from Texas Instruments
5478 include internal flash and use ARM7TDMI cores.
5479 This driver doesn't require the chip and bus width to be specified.
5481 Some tms470-specific commands are defined:
5483 @deffn Command {tms470 flash_keyset} key0 key1 key2 key3
5484 Saves programming keys in a register, to enable flash erase and write commands.
5487 @deffn Command {tms470 osc_mhz} clock_mhz
5488 Reports the clock speed, which is used to calculate timings.
5491 @deffn Command {tms470 plldis} (0|1)
5492 Disables (@var{1}) or enables (@var{0}) use of the PLL to speed up
5497 @deffn {Flash Driver} virtual
5498 This is a special driver that maps a previously defined bank to another
5499 address. All bank settings will be copied from the master physical bank.
5501 The @var{virtual} driver defines one mandatory parameters,
5504 @item @var{master_bank} The bank that this virtual address refers to.
5507 So in the following example addresses 0xbfc00000 and 0x9fc00000 refer to
5508 the flash bank defined at address 0x1fc00000. Any cmds executed on
5509 the virtual banks are actually performed on the physical banks.
5511 flash bank $_FLASHNAME pic32mx 0x1fc00000 0 0 0 $_TARGETNAME
5512 flash bank vbank0 virtual 0xbfc00000 0 0 0 $_TARGETNAME $_FLASHNAME
5513 flash bank vbank1 virtual 0x9fc00000 0 0 0 $_TARGETNAME $_FLASHNAME
5517 @deffn {Flash Driver} fm3
5518 All members of the FM3 microcontroller family from Fujitsu
5519 include internal flash and use ARM Cortex M3 cores.
5520 The @var{fm3} driver uses the @var{target} parameter to select the
5521 correct bank config, it can currently be one of the following:
5522 @code{mb9bfxx1.cpu}, @code{mb9bfxx2.cpu}, @code{mb9bfxx3.cpu},
5523 @code{mb9bfxx4.cpu}, @code{mb9bfxx5.cpu} or @code{mb9bfxx6.cpu}.
5526 flash bank $_FLASHNAME fm3 0 0 0 0 $_TARGETNAME
5530 @subsection str9xpec driver
5533 Here is some background info to help
5534 you better understand how this driver works. OpenOCD has two flash drivers for
5538 Standard driver @option{str9x} programmed via the str9 core. Normally used for
5539 flash programming as it is faster than the @option{str9xpec} driver.
5541 Direct programming @option{str9xpec} using the flash controller. This is an
5542 ISC compilant (IEEE 1532) tap connected in series with the str9 core. The str9
5543 core does not need to be running to program using this flash driver. Typical use
5544 for this driver is locking/unlocking the target and programming the option bytes.
5547 Before we run any commands using the @option{str9xpec} driver we must first disable
5548 the str9 core. This example assumes the @option{str9xpec} driver has been
5549 configured for flash bank 0.
5551 # assert srst, we do not want core running
5552 # while accessing str9xpec flash driver
5554 # turn off target polling
5557 str9xpec enable_turbo 0
5559 str9xpec options_read 0
5560 # re-enable str9 core
5561 str9xpec disable_turbo 0
5565 The above example will read the str9 option bytes.
5566 When performing a unlock remember that you will not be able to halt the str9 - it
5567 has been locked. Halting the core is not required for the @option{str9xpec} driver
5568 as mentioned above, just issue the commands above manually or from a telnet prompt.
5570 @deffn {Flash Driver} str9xpec
5571 Only use this driver for locking/unlocking the device or configuring the option bytes.
5572 Use the standard str9 driver for programming.
5573 Before using the flash commands the turbo mode must be enabled using the
5574 @command{str9xpec enable_turbo} command.
5576 Several str9xpec-specific commands are defined:
5578 @deffn Command {str9xpec disable_turbo} num
5579 Restore the str9 into JTAG chain.
5582 @deffn Command {str9xpec enable_turbo} num
5583 Enable turbo mode, will simply remove the str9 from the chain and talk
5584 directly to the embedded flash controller.
5587 @deffn Command {str9xpec lock} num
5588 Lock str9 device. The str9 will only respond to an unlock command that will
5592 @deffn Command {str9xpec part_id} num
5593 Prints the part identifier for bank @var{num}.
5596 @deffn Command {str9xpec options_cmap} num (@option{bank0}|@option{bank1})
5597 Configure str9 boot bank.
5600 @deffn Command {str9xpec options_lvdsel} num (@option{vdd}|@option{vdd_vddq})
5601 Configure str9 lvd source.
5604 @deffn Command {str9xpec options_lvdthd} num (@option{2.4v}|@option{2.7v})
5605 Configure str9 lvd threshold.
5608 @deffn Command {str9xpec options_lvdwarn} bank (@option{vdd}|@option{vdd_vddq})
5609 Configure str9 lvd reset warning source.
5612 @deffn Command {str9xpec options_read} num
5613 Read str9 option bytes.
5616 @deffn Command {str9xpec options_write} num
5617 Write str9 option bytes.
5620 @deffn Command {str9xpec unlock} num
5629 @subsection mFlash Configuration
5630 @cindex mFlash Configuration
5632 @deffn {Config Command} {mflash bank} soc base RST_pin target
5633 Configures a mflash for @var{soc} host bank at
5635 The pin number format depends on the host GPIO naming convention.
5636 Currently, the mflash driver supports s3c2440 and pxa270.
5638 Example for s3c2440 mflash where @var{RST pin} is GPIO B1:
5641 mflash bank $_FLASHNAME s3c2440 0x10000000 1b 0
5644 Example for pxa270 mflash where @var{RST pin} is GPIO 43:
5647 mflash bank $_FLASHNAME pxa270 0x08000000 43 0
5651 @subsection mFlash commands
5652 @cindex mFlash commands
5654 @deffn Command {mflash config pll} frequency
5655 Configure mflash PLL.
5656 The @var{frequency} is the mflash input frequency, in Hz.
5657 Issuing this command will erase mflash's whole internal nand and write new pll.
5658 After this command, mflash needs power-on-reset for normal operation.
5659 If pll was newly configured, storage and boot(optional) info also need to be update.
5662 @deffn Command {mflash config boot}
5663 Configure bootable option.
5664 If bootable option is set, mflash offer the first 8 sectors
5668 @deffn Command {mflash config storage}
5669 Configure storage information.
5670 For the normal storage operation, this information must be
5674 @deffn Command {mflash dump} num filename offset size
5675 Dump @var{size} bytes, starting at @var{offset} bytes from the
5676 beginning of the bank @var{num}, to the file named @var{filename}.
5679 @deffn Command {mflash probe}
5683 @deffn Command {mflash write} num filename offset
5684 Write the binary file @var{filename} to mflash bank @var{num}, starting at
5685 @var{offset} bytes from the beginning of the bank.
5688 @node Flash Programming
5689 @chapter Flash Programming
5691 OpenOCD implements numerous ways to program the target flash, whether internal or external.
5692 Programming can be acheived by either using GDB @ref{programmingusinggdb,,Programming using GDB},
5693 or using the cmds given in @ref{flashprogrammingcommands,,Flash Programming Commands}.
5695 @*To simplify using the flash cmds directly a jimtcl script is available that handles the programming and verify stage.
5696 OpenOCD will program/verify/reset the target and shutdown.
5698 The script is executed as follows and by default the following actions will be peformed.
5700 @item 'init' is executed.
5701 @item 'reset init' is called to reset and halt the target, any 'reset init' scripts are executed.
5702 @item @code{flash write_image} is called to erase and write any flash using the filename given.
5703 @item @code{verify_image} is called if @option{verify} parameter is given.
5704 @item @code{reset run} is called if @option{reset} parameter is given.
5705 @item OpenOCD is shutdown.
5708 An example of usage is given below. @xref{program}.
5711 # program and verify using elf/hex/s19. verify and reset
5712 # are optional parameters
5713 openocd -f board/stm32f3discovery.cfg \
5714 -c "program filename.elf verify reset"
5716 # binary files need the flash address passing
5717 openocd -f board/stm32f3discovery.cfg \
5718 -c "program filename.bin 0x08000000"
5721 @node NAND Flash Commands
5722 @chapter NAND Flash Commands
5725 Compared to NOR or SPI flash, NAND devices are inexpensive
5726 and high density. Today's NAND chips, and multi-chip modules,
5727 commonly hold multiple GigaBytes of data.
5729 NAND chips consist of a number of ``erase blocks'' of a given
5730 size (such as 128 KBytes), each of which is divided into a
5731 number of pages (of perhaps 512 or 2048 bytes each). Each
5732 page of a NAND flash has an ``out of band'' (OOB) area to hold
5733 Error Correcting Code (ECC) and other metadata, usually 16 bytes
5734 of OOB for every 512 bytes of page data.
5736 One key characteristic of NAND flash is that its error rate
5737 is higher than that of NOR flash. In normal operation, that
5738 ECC is used to correct and detect errors. However, NAND
5739 blocks can also wear out and become unusable; those blocks
5740 are then marked "bad". NAND chips are even shipped from the
5741 manufacturer with a few bad blocks. The highest density chips
5742 use a technology (MLC) that wears out more quickly, so ECC
5743 support is increasingly important as a way to detect blocks
5744 that have begun to fail, and help to preserve data integrity
5745 with techniques such as wear leveling.
5747 Software is used to manage the ECC. Some controllers don't
5748 support ECC directly; in those cases, software ECC is used.
5749 Other controllers speed up the ECC calculations with hardware.
5750 Single-bit error correction hardware is routine. Controllers
5751 geared for newer MLC chips may correct 4 or more errors for
5752 every 512 bytes of data.
5754 You will need to make sure that any data you write using
5755 OpenOCD includes the apppropriate kind of ECC. For example,
5756 that may mean passing the @code{oob_softecc} flag when
5757 writing NAND data, or ensuring that the correct hardware
5760 The basic steps for using NAND devices include:
5762 @item Declare via the command @command{nand device}
5763 @* Do this in a board-specific configuration file,
5764 passing parameters as needed by the controller.
5765 @item Configure each device using @command{nand probe}.
5766 @* Do this only after the associated target is set up,
5767 such as in its reset-init script or in procures defined
5768 to access that device.
5769 @item Operate on the flash via @command{nand subcommand}
5770 @* Often commands to manipulate the flash are typed by a human, or run
5771 via a script in some automated way. Common task include writing a
5772 boot loader, operating system, or other data needed to initialize or
5776 @b{NOTE:} At the time this text was written, the largest NAND
5777 flash fully supported by OpenOCD is 2 GiBytes (16 GiBits).
5778 This is because the variables used to hold offsets and lengths
5779 are only 32 bits wide.
5780 (Larger chips may work in some cases, unless an offset or length
5781 is larger than 0xffffffff, the largest 32-bit unsigned integer.)
5782 Some larger devices will work, since they are actually multi-chip
5783 modules with two smaller chips and individual chipselect lines.
5785 @anchor{nandconfiguration}
5786 @section NAND Configuration Commands
5787 @cindex NAND configuration
5789 NAND chips must be declared in configuration scripts,
5790 plus some additional configuration that's done after
5791 OpenOCD has initialized.
5793 @deffn {Config Command} {nand device} name driver target [configparams...]
5794 Declares a NAND device, which can be read and written to
5795 after it has been configured through @command{nand probe}.
5796 In OpenOCD, devices are single chips; this is unlike some
5797 operating systems, which may manage multiple chips as if
5798 they were a single (larger) device.
5799 In some cases, configuring a device will activate extra
5800 commands; see the controller-specific documentation.
5802 @b{NOTE:} This command is not available after OpenOCD
5803 initialization has completed. Use it in board specific
5804 configuration files, not interactively.
5807 @item @var{name} ... may be used to reference the NAND bank
5808 in most other NAND commands. A number is also available.
5809 @item @var{driver} ... identifies the NAND controller driver
5810 associated with the NAND device being declared.
5811 @xref{nanddriverlist,,NAND Driver List}.
5812 @item @var{target} ... names the target used when issuing
5813 commands to the NAND controller.
5814 @comment Actually, it's currently a controller-specific parameter...
5815 @item @var{configparams} ... controllers may support, or require,
5816 additional parameters. See the controller-specific documentation
5817 for more information.
5821 @deffn Command {nand list}
5822 Prints a summary of each device declared
5823 using @command{nand device}, numbered from zero.
5824 Note that un-probed devices show no details.
5827 #0: NAND 1GiB 3,3V 8-bit (Micron) pagesize: 2048, buswidth: 8,
5828 blocksize: 131072, blocks: 8192
5829 #1: NAND 1GiB 3,3V 8-bit (Micron) pagesize: 2048, buswidth: 8,
5830 blocksize: 131072, blocks: 8192
5835 @deffn Command {nand probe} num
5836 Probes the specified device to determine key characteristics
5837 like its page and block sizes, and how many blocks it has.
5838 The @var{num} parameter is the value shown by @command{nand list}.
5839 You must (successfully) probe a device before you can use
5840 it with most other NAND commands.
5843 @section Erasing, Reading, Writing to NAND Flash
5845 @deffn Command {nand dump} num filename offset length [oob_option]
5846 @cindex NAND reading
5847 Reads binary data from the NAND device and writes it to the file,
5848 starting at the specified offset.
5849 The @var{num} parameter is the value shown by @command{nand list}.
5851 Use a complete path name for @var{filename}, so you don't depend
5852 on the directory used to start the OpenOCD server.
5854 The @var{offset} and @var{length} must be exact multiples of the
5855 device's page size. They describe a data region; the OOB data
5856 associated with each such page may also be accessed.
5858 @b{NOTE:} At the time this text was written, no error correction
5859 was done on the data that's read, unless raw access was disabled
5860 and the underlying NAND controller driver had a @code{read_page}
5861 method which handled that error correction.
5863 By default, only page data is saved to the specified file.
5864 Use an @var{oob_option} parameter to save OOB data:
5866 @item no oob_* parameter
5867 @*Output file holds only page data; OOB is discarded.
5868 @item @code{oob_raw}
5869 @*Output file interleaves page data and OOB data;
5870 the file will be longer than "length" by the size of the
5871 spare areas associated with each data page.
5872 Note that this kind of "raw" access is different from
5873 what's implied by @command{nand raw_access}, which just
5874 controls whether a hardware-aware access method is used.
5875 @item @code{oob_only}
5876 @*Output file has only raw OOB data, and will
5877 be smaller than "length" since it will contain only the
5878 spare areas associated with each data page.
5882 @deffn Command {nand erase} num [offset length]
5883 @cindex NAND erasing
5884 @cindex NAND programming
5885 Erases blocks on the specified NAND device, starting at the
5886 specified @var{offset} and continuing for @var{length} bytes.
5887 Both of those values must be exact multiples of the device's
5888 block size, and the region they specify must fit entirely in the chip.
5889 If those parameters are not specified,
5890 the whole NAND chip will be erased.
5891 The @var{num} parameter is the value shown by @command{nand list}.
5893 @b{NOTE:} This command will try to erase bad blocks, when told
5894 to do so, which will probably invalidate the manufacturer's bad
5896 For the remainder of the current server session, @command{nand info}
5897 will still report that the block ``is'' bad.
5900 @deffn Command {nand write} num filename offset [option...]
5901 @cindex NAND writing
5902 @cindex NAND programming
5903 Writes binary data from the file into the specified NAND device,
5904 starting at the specified offset. Those pages should already
5905 have been erased; you can't change zero bits to one bits.
5906 The @var{num} parameter is the value shown by @command{nand list}.
5908 Use a complete path name for @var{filename}, so you don't depend
5909 on the directory used to start the OpenOCD server.
5911 The @var{offset} must be an exact multiple of the device's page size.
5912 All data in the file will be written, assuming it doesn't run
5913 past the end of the device.
5914 Only full pages are written, and any extra space in the last
5915 page will be filled with 0xff bytes. (That includes OOB data,
5916 if that's being written.)
5918 @b{NOTE:} At the time this text was written, bad blocks are
5919 ignored. That is, this routine will not skip bad blocks,
5920 but will instead try to write them. This can cause problems.
5922 Provide at most one @var{option} parameter. With some
5923 NAND drivers, the meanings of these parameters may change
5924 if @command{nand raw_access} was used to disable hardware ECC.
5926 @item no oob_* parameter
5927 @*File has only page data, which is written.
5928 If raw acccess is in use, the OOB area will not be written.
5929 Otherwise, if the underlying NAND controller driver has
5930 a @code{write_page} routine, that routine may write the OOB
5931 with hardware-computed ECC data.
5932 @item @code{oob_only}
5933 @*File has only raw OOB data, which is written to the OOB area.
5934 Each page's data area stays untouched. @i{This can be a dangerous
5935 option}, since it can invalidate the ECC data.
5936 You may need to force raw access to use this mode.
5937 @item @code{oob_raw}
5938 @*File interleaves data and OOB data, both of which are written
5939 If raw access is enabled, the data is written first, then the
5941 Otherwise, if the underlying NAND controller driver has
5942 a @code{write_page} routine, that routine may modify the OOB
5943 before it's written, to include hardware-computed ECC data.
5944 @item @code{oob_softecc}
5945 @*File has only page data, which is written.
5946 The OOB area is filled with 0xff, except for a standard 1-bit
5947 software ECC code stored in conventional locations.
5948 You might need to force raw access to use this mode, to prevent
5949 the underlying driver from applying hardware ECC.
5950 @item @code{oob_softecc_kw}
5951 @*File has only page data, which is written.
5952 The OOB area is filled with 0xff, except for a 4-bit software ECC
5953 specific to the boot ROM in Marvell Kirkwood SoCs.
5954 You might need to force raw access to use this mode, to prevent
5955 the underlying driver from applying hardware ECC.
5959 @deffn Command {nand verify} num filename offset [option...]
5960 @cindex NAND verification
5961 @cindex NAND programming
5962 Verify the binary data in the file has been programmed to the
5963 specified NAND device, starting at the specified offset.
5964 The @var{num} parameter is the value shown by @command{nand list}.
5966 Use a complete path name for @var{filename}, so you don't depend
5967 on the directory used to start the OpenOCD server.
5969 The @var{offset} must be an exact multiple of the device's page size.
5970 All data in the file will be read and compared to the contents of the
5971 flash, assuming it doesn't run past the end of the device.
5972 As with @command{nand write}, only full pages are verified, so any extra
5973 space in the last page will be filled with 0xff bytes.
5975 The same @var{options} accepted by @command{nand write},
5976 and the file will be processed similarly to produce the buffers that
5977 can be compared against the contents produced from @command{nand dump}.
5979 @b{NOTE:} This will not work when the underlying NAND controller
5980 driver's @code{write_page} routine must update the OOB with a
5981 hardward-computed ECC before the data is written. This limitation may
5982 be removed in a future release.
5985 @section Other NAND commands
5986 @cindex NAND other commands
5988 @deffn Command {nand check_bad_blocks} num [offset length]
5989 Checks for manufacturer bad block markers on the specified NAND
5990 device. If no parameters are provided, checks the whole
5991 device; otherwise, starts at the specified @var{offset} and
5992 continues for @var{length} bytes.
5993 Both of those values must be exact multiples of the device's
5994 block size, and the region they specify must fit entirely in the chip.
5995 The @var{num} parameter is the value shown by @command{nand list}.
5997 @b{NOTE:} Before using this command you should force raw access
5998 with @command{nand raw_access enable} to ensure that the underlying
5999 driver will not try to apply hardware ECC.
6002 @deffn Command {nand info} num
6003 The @var{num} parameter is the value shown by @command{nand list}.
6004 This prints the one-line summary from "nand list", plus for
6005 devices which have been probed this also prints any known
6006 status for each block.
6009 @deffn Command {nand raw_access} num (@option{enable}|@option{disable})
6010 Sets or clears an flag affecting how page I/O is done.
6011 The @var{num} parameter is the value shown by @command{nand list}.
6013 This flag is cleared (disabled) by default, but changing that
6014 value won't affect all NAND devices. The key factor is whether
6015 the underlying driver provides @code{read_page} or @code{write_page}
6016 methods. If it doesn't provide those methods, the setting of
6017 this flag is irrelevant; all access is effectively ``raw''.
6019 When those methods exist, they are normally used when reading
6020 data (@command{nand dump} or reading bad block markers) or
6021 writing it (@command{nand write}). However, enabling
6022 raw access (setting the flag) prevents use of those methods,
6023 bypassing hardware ECC logic.
6024 @i{This can be a dangerous option}, since writing blocks
6025 with the wrong ECC data can cause them to be marked as bad.
6028 @anchor{nanddriverlist}
6029 @section NAND Driver List
6030 As noted above, the @command{nand device} command allows
6031 driver-specific options and behaviors.
6032 Some controllers also activate controller-specific commands.
6034 @deffn {NAND Driver} at91sam9
6035 This driver handles the NAND controllers found on AT91SAM9 family chips from
6036 Atmel. It takes two extra parameters: address of the NAND chip;
6037 address of the ECC controller.
6039 nand device $NANDFLASH at91sam9 $CHIPNAME 0x40000000 0xfffffe800
6041 AT91SAM9 chips support single-bit ECC hardware. The @code{write_page} and
6042 @code{read_page} methods are used to utilize the ECC hardware unless they are
6043 disabled by using the @command{nand raw_access} command. There are four
6044 additional commands that are needed to fully configure the AT91SAM9 NAND
6045 controller. Two are optional; most boards use the same wiring for ALE/CLE:
6046 @deffn Command {at91sam9 cle} num addr_line
6047 Configure the address line used for latching commands. The @var{num}
6048 parameter is the value shown by @command{nand list}.
6050 @deffn Command {at91sam9 ale} num addr_line
6051 Configure the address line used for latching addresses. The @var{num}
6052 parameter is the value shown by @command{nand list}.
6055 For the next two commands, it is assumed that the pins have already been
6056 properly configured for input or output.
6057 @deffn Command {at91sam9 rdy_busy} num pio_base_addr pin
6058 Configure the RDY/nBUSY input from the NAND device. The @var{num}
6059 parameter is the value shown by @command{nand list}. @var{pio_base_addr}
6060 is the base address of the PIO controller and @var{pin} is the pin number.
6062 @deffn Command {at91sam9 ce} num pio_base_addr pin
6063 Configure the chip enable input to the NAND device. The @var{num}
6064 parameter is the value shown by @command{nand list}. @var{pio_base_addr}
6065 is the base address of the PIO controller and @var{pin} is the pin number.
6069 @deffn {NAND Driver} davinci
6070 This driver handles the NAND controllers found on DaVinci family
6071 chips from Texas Instruments.
6072 It takes three extra parameters:
6073 address of the NAND chip;
6074 hardware ECC mode to use (@option{hwecc1},
6075 @option{hwecc4}, @option{hwecc4_infix});
6076 address of the AEMIF controller on this processor.
6078 nand device davinci dm355.arm 0x02000000 hwecc4 0x01e10000
6080 All DaVinci processors support the single-bit ECC hardware,
6081 and newer ones also support the four-bit ECC hardware.
6082 The @code{write_page} and @code{read_page} methods are used
6083 to implement those ECC modes, unless they are disabled using
6084 the @command{nand raw_access} command.
6087 @deffn {NAND Driver} lpc3180
6088 These controllers require an extra @command{nand device}
6089 parameter: the clock rate used by the controller.
6090 @deffn Command {lpc3180 select} num [mlc|slc]
6091 Configures use of the MLC or SLC controller mode.
6092 MLC implies use of hardware ECC.
6093 The @var{num} parameter is the value shown by @command{nand list}.
6096 At this writing, this driver includes @code{write_page}
6097 and @code{read_page} methods. Using @command{nand raw_access}
6098 to disable those methods will prevent use of hardware ECC
6099 in the MLC controller mode, but won't change SLC behavior.
6101 @comment current lpc3180 code won't issue 5-byte address cycles
6103 @deffn {NAND Driver} mx3
6104 This driver handles the NAND controller in i.MX31. The mxc driver
6105 should work for this chip aswell.
6108 @deffn {NAND Driver} mxc
6109 This driver handles the NAND controller found in Freescale i.MX
6110 chips. It has support for v1 (i.MX27 and i.MX31) and v2 (i.MX35).
6111 The driver takes 3 extra arguments, chip (@option{mx27},
6112 @option{mx31}, @option{mx35}), ecc (@option{noecc}, @option{hwecc})
6113 and optionally if bad block information should be swapped between
6114 main area and spare area (@option{biswap}), defaults to off.
6116 nand device mx35.nand mxc imx35.cpu mx35 hwecc biswap
6118 @deffn Command {mxc biswap} bank_num [enable|disable]
6119 Turns on/off bad block information swaping from main area,
6120 without parameter query status.
6124 @deffn {NAND Driver} orion
6125 These controllers require an extra @command{nand device}
6126 parameter: the address of the controller.
6128 nand device orion 0xd8000000
6130 These controllers don't define any specialized commands.
6131 At this writing, their drivers don't include @code{write_page}
6132 or @code{read_page} methods, so @command{nand raw_access} won't
6133 change any behavior.
6136 @deffn {NAND Driver} s3c2410
6137 @deffnx {NAND Driver} s3c2412
6138 @deffnx {NAND Driver} s3c2440
6139 @deffnx {NAND Driver} s3c2443
6140 @deffnx {NAND Driver} s3c6400
6141 These S3C family controllers don't have any special
6142 @command{nand device} options, and don't define any
6143 specialized commands.
6144 At this writing, their drivers don't include @code{write_page}
6145 or @code{read_page} methods, so @command{nand raw_access} won't
6146 change any behavior.
6149 @node PLD/FPGA Commands
6150 @chapter PLD/FPGA Commands
6154 Programmable Logic Devices (PLDs) and the more flexible
6155 Field Programmable Gate Arrays (FPGAs) are both types of programmable hardware.
6156 OpenOCD can support programming them.
6157 Although PLDs are generally restrictive (cells are less functional, and
6158 there are no special purpose cells for memory or computational tasks),
6159 they share the same OpenOCD infrastructure.
6160 Accordingly, both are called PLDs here.
6162 @section PLD/FPGA Configuration and Commands
6164 As it does for JTAG TAPs, debug targets, and flash chips (both NOR and NAND),
6165 OpenOCD maintains a list of PLDs available for use in various commands.
6166 Also, each such PLD requires a driver.
6168 They are referenced by the number shown by the @command{pld devices} command,
6169 and new PLDs are defined by @command{pld device driver_name}.
6171 @deffn {Config Command} {pld device} driver_name tap_name [driver_options]
6172 Defines a new PLD device, supported by driver @var{driver_name},
6173 using the TAP named @var{tap_name}.
6174 The driver may make use of any @var{driver_options} to configure its
6178 @deffn {Command} {pld devices}
6179 Lists the PLDs and their numbers.
6182 @deffn {Command} {pld load} num filename
6183 Loads the file @file{filename} into the PLD identified by @var{num}.
6184 The file format must be inferred by the driver.
6187 @section PLD/FPGA Drivers, Options, and Commands
6189 Drivers may support PLD-specific options to the @command{pld device}
6190 definition command, and may also define commands usable only with
6191 that particular type of PLD.
6193 @deffn {FPGA Driver} virtex2
6194 Virtex-II is a family of FPGAs sold by Xilinx.
6195 It supports the IEEE 1532 standard for In-System Configuration (ISC).
6196 No driver-specific PLD definition options are used,
6197 and one driver-specific command is defined.
6199 @deffn {Command} {virtex2 read_stat} num
6200 Reads and displays the Virtex-II status register (STAT)
6205 @node General Commands
6206 @chapter General Commands
6209 The commands documented in this chapter here are common commands that
6210 you, as a human, may want to type and see the output of. Configuration type
6211 commands are documented elsewhere.
6215 @item @b{Source Of Commands}
6216 @* OpenOCD commands can occur in a configuration script (discussed
6217 elsewhere) or typed manually by a human or supplied programatically,
6218 or via one of several TCP/IP Ports.
6220 @item @b{From the human}
6221 @* A human should interact with the telnet interface (default port: 4444)
6222 or via GDB (default port 3333).
6224 To issue commands from within a GDB session, use the @option{monitor}
6225 command, e.g. use @option{monitor poll} to issue the @option{poll}
6226 command. All output is relayed through the GDB session.
6228 @item @b{Machine Interface}
6229 The Tcl interface's intent is to be a machine interface. The default Tcl
6234 @section Daemon Commands
6236 @deffn {Command} exit
6237 Exits the current telnet session.
6240 @deffn {Command} help [string]
6241 With no parameters, prints help text for all commands.
6242 Otherwise, prints each helptext containing @var{string}.
6243 Not every command provides helptext.
6245 Configuration commands, and commands valid at any time, are
6246 explicitly noted in parenthesis.
6247 In most cases, no such restriction is listed; this indicates commands
6248 which are only available after the configuration stage has completed.
6251 @deffn Command sleep msec [@option{busy}]
6252 Wait for at least @var{msec} milliseconds before resuming.
6253 If @option{busy} is passed, busy-wait instead of sleeping.
6254 (This option is strongly discouraged.)
6255 Useful in connection with script files
6256 (@command{script} command and @command{target_name} configuration).
6259 @deffn Command shutdown
6260 Close the OpenOCD daemon, disconnecting all clients (GDB, telnet, other).
6264 @deffn Command debug_level [n]
6265 @cindex message level
6266 Display debug level.
6267 If @var{n} (from 0..3) is provided, then set it to that level.
6268 This affects the kind of messages sent to the server log.
6269 Level 0 is error messages only;
6270 level 1 adds warnings;
6271 level 2 adds informational messages;
6272 and level 3 adds debugging messages.
6273 The default is level 2, but that can be overridden on
6274 the command line along with the location of that log
6275 file (which is normally the server's standard output).
6279 @deffn Command echo [-n] message
6280 Logs a message at "user" priority.
6281 Output @var{message} to stdout.
6282 Option "-n" suppresses trailing newline.
6284 echo "Downloading kernel -- please wait"
6288 @deffn Command log_output [filename]
6289 Redirect logging to @var{filename};
6290 the initial log output channel is stderr.
6293 @deffn Command add_script_search_dir [directory]
6294 Add @var{directory} to the file/script search path.
6297 @anchor{targetstatehandling}
6298 @section Target State handling
6301 @cindex target initialization
6303 In this section ``target'' refers to a CPU configured as
6304 shown earlier (@pxref{CPU Configuration}).
6305 These commands, like many, implicitly refer to
6306 a current target which is used to perform the
6307 various operations. The current target may be changed
6308 by using @command{targets} command with the name of the
6309 target which should become current.
6311 @deffn Command reg [(number|name) [value]]
6312 Access a single register by @var{number} or by its @var{name}.
6313 The target must generally be halted before access to CPU core
6314 registers is allowed. Depending on the hardware, some other
6315 registers may be accessible while the target is running.
6317 @emph{With no arguments}:
6318 list all available registers for the current target,
6319 showing number, name, size, value, and cache status.
6320 For valid entries, a value is shown; valid entries
6321 which are also dirty (and will be written back later)
6322 are flagged as such.
6324 @emph{With number/name}: display that register's value.
6326 @emph{With both number/name and value}: set register's value.
6327 Writes may be held in a writeback cache internal to OpenOCD,
6328 so that setting the value marks the register as dirty instead
6329 of immediately flushing that value. Resuming CPU execution
6330 (including by single stepping) or otherwise activating the
6331 relevant module will flush such values.
6333 Cores may have surprisingly many registers in their
6334 Debug and trace infrastructure:
6339 (0) r0 (/32): 0x0000D3C2 (dirty)
6340 (1) r1 (/32): 0xFD61F31C
6343 (164) ETM_contextid_comparator_mask (/32)
6348 @deffn Command halt [ms]
6349 @deffnx Command wait_halt [ms]
6350 The @command{halt} command first sends a halt request to the target,
6351 which @command{wait_halt} doesn't.
6352 Otherwise these behave the same: wait up to @var{ms} milliseconds,
6353 or 5 seconds if there is no parameter, for the target to halt
6354 (and enter debug mode).
6355 Using 0 as the @var{ms} parameter prevents OpenOCD from waiting.
6358 On ARM cores, software using the @emph{wait for interrupt} operation
6359 often blocks the JTAG access needed by a @command{halt} command.
6360 This is because that operation also puts the core into a low
6361 power mode by gating the core clock;
6362 but the core clock is needed to detect JTAG clock transitions.
6364 One partial workaround uses adaptive clocking: when the core is
6365 interrupted the operation completes, then JTAG clocks are accepted
6366 at least until the interrupt handler completes.
6367 However, this workaround is often unusable since the processor, board,
6368 and JTAG adapter must all support adaptive JTAG clocking.
6369 Also, it can't work until an interrupt is issued.
6371 A more complete workaround is to not use that operation while you
6372 work with a JTAG debugger.
6373 Tasking environments generaly have idle loops where the body is the
6374 @emph{wait for interrupt} operation.
6375 (On older cores, it is a coprocessor action;
6376 newer cores have a @option{wfi} instruction.)
6377 Such loops can just remove that operation, at the cost of higher
6378 power consumption (because the CPU is needlessly clocked).
6383 @deffn Command resume [address]
6384 Resume the target at its current code position,
6385 or the optional @var{address} if it is provided.
6386 OpenOCD will wait 5 seconds for the target to resume.
6389 @deffn Command step [address]
6390 Single-step the target at its current code position,
6391 or the optional @var{address} if it is provided.
6394 @anchor{resetcommand}
6395 @deffn Command reset
6396 @deffnx Command {reset run}
6397 @deffnx Command {reset halt}
6398 @deffnx Command {reset init}
6399 Perform as hard a reset as possible, using SRST if possible.
6400 @emph{All defined targets will be reset, and target
6401 events will fire during the reset sequence.}
6403 The optional parameter specifies what should
6404 happen after the reset.
6405 If there is no parameter, a @command{reset run} is executed.
6406 The other options will not work on all systems.
6407 @xref{Reset Configuration}.
6410 @item @b{run} Let the target run
6411 @item @b{halt} Immediately halt the target
6412 @item @b{init} Immediately halt the target, and execute the reset-init script
6416 @deffn Command soft_reset_halt
6417 Requesting target halt and executing a soft reset. This is often used
6418 when a target cannot be reset and halted. The target, after reset is
6419 released begins to execute code. OpenOCD attempts to stop the CPU and
6420 then sets the program counter back to the reset vector. Unfortunately
6421 the code that was executed may have left the hardware in an unknown
6425 @section I/O Utilities
6427 These commands are available when
6428 OpenOCD is built with @option{--enable-ioutil}.
6429 They are mainly useful on embedded targets,
6431 Hosts with operating systems have complementary tools.
6433 @emph{Note:} there are several more such commands.
6435 @deffn Command append_file filename [string]*
6436 Appends the @var{string} parameters to
6437 the text file @file{filename}.
6438 Each string except the last one is followed by one space.
6439 The last string is followed by a newline.
6442 @deffn Command cat filename
6443 Reads and displays the text file @file{filename}.
6446 @deffn Command cp src_filename dest_filename
6447 Copies contents from the file @file{src_filename}
6448 into @file{dest_filename}.
6452 @emph{No description provided.}
6456 @emph{No description provided.}
6460 @emph{No description provided.}
6463 @deffn Command meminfo
6464 Display available RAM memory on OpenOCD host.
6465 Used in OpenOCD regression testing scripts.
6469 @emph{No description provided.}
6473 @emph{No description provided.}
6476 @deffn Command rm filename
6477 @c "rm" has both normal and Jim-level versions??
6478 Unlinks the file @file{filename}.
6481 @deffn Command trunc filename
6482 Removes all data in the file @file{filename}.
6485 @anchor{memoryaccess}
6486 @section Memory access commands
6487 @cindex memory access
6489 These commands allow accesses of a specific size to the memory
6490 system. Often these are used to configure the current target in some
6491 special way. For example - one may need to write certain values to the
6492 SDRAM controller to enable SDRAM.
6495 @item Use the @command{targets} (plural) command
6496 to change the current target.
6497 @item In system level scripts these commands are deprecated.
6498 Please use their TARGET object siblings to avoid making assumptions
6499 about what TAP is the current target, or about MMU configuration.
6502 @deffn Command mdw [phys] addr [count]
6503 @deffnx Command mdh [phys] addr [count]
6504 @deffnx Command mdb [phys] addr [count]
6505 Display contents of address @var{addr}, as
6506 32-bit words (@command{mdw}), 16-bit halfwords (@command{mdh}),
6507 or 8-bit bytes (@command{mdb}).
6508 When the current target has an MMU which is present and active,
6509 @var{addr} is interpreted as a virtual address.
6510 Otherwise, or if the optional @var{phys} flag is specified,
6511 @var{addr} is interpreted as a physical address.
6512 If @var{count} is specified, displays that many units.
6513 (If you want to manipulate the data instead of displaying it,
6514 see the @code{mem2array} primitives.)
6517 @deffn Command mww [phys] addr word
6518 @deffnx Command mwh [phys] addr halfword
6519 @deffnx Command mwb [phys] addr byte
6520 Writes the specified @var{word} (32 bits),
6521 @var{halfword} (16 bits), or @var{byte} (8-bit) value,
6522 at the specified address @var{addr}.
6523 When the current target has an MMU which is present and active,
6524 @var{addr} is interpreted as a virtual address.
6525 Otherwise, or if the optional @var{phys} flag is specified,
6526 @var{addr} is interpreted as a physical address.
6529 @anchor{imageaccess}
6530 @section Image loading commands
6531 @cindex image loading
6532 @cindex image dumping
6534 @deffn Command {dump_image} filename address size
6535 Dump @var{size} bytes of target memory starting at @var{address} to the
6536 binary file named @var{filename}.
6539 @deffn Command {fast_load}
6540 Loads an image stored in memory by @command{fast_load_image} to the
6541 current target. Must be preceeded by fast_load_image.
6544 @deffn Command {fast_load_image} filename address [@option{bin}|@option{ihex}|@option{elf}|@option{s19}]
6545 Normally you should be using @command{load_image} or GDB load. However, for
6546 testing purposes or when I/O overhead is significant(OpenOCD running on an embedded
6547 host), storing the image in memory and uploading the image to the target
6548 can be a way to upload e.g. multiple debug sessions when the binary does not change.
6549 Arguments are the same as @command{load_image}, but the image is stored in OpenOCD host
6550 memory, i.e. does not affect target. This approach is also useful when profiling
6551 target programming performance as I/O and target programming can easily be profiled
6555 @deffn Command {load_image} filename address [[@option{bin}|@option{ihex}|@option{elf}|@option{s19}] @option{min_addr} @option{max_length}]
6556 Load image from file @var{filename} to target memory offset by @var{address} from its load address.
6557 The file format may optionally be specified
6558 (@option{bin}, @option{ihex}, @option{elf}, or @option{s19}).
6559 In addition the following arguments may be specifed:
6560 @var{min_addr} - ignore data below @var{min_addr} (this is w.r.t. to the target's load address + @var{address})
6561 @var{max_length} - maximum number of bytes to load.
6563 proc load_image_bin @{fname foffset address length @} @{
6564 # Load data from fname filename at foffset offset to
6565 # target at address. Load at most length bytes.
6566 load_image $fname [expr $address - $foffset] bin $address $length
6571 @deffn Command {test_image} filename [address [@option{bin}|@option{ihex}|@option{elf}]]
6572 Displays image section sizes and addresses
6573 as if @var{filename} were loaded into target memory
6574 starting at @var{address} (defaults to zero).
6575 The file format may optionally be specified
6576 (@option{bin}, @option{ihex}, or @option{elf})
6579 @deffn Command {verify_image} filename address [@option{bin}|@option{ihex}|@option{elf}]
6580 Verify @var{filename} against target memory starting at @var{address}.
6581 The file format may optionally be specified
6582 (@option{bin}, @option{ihex}, or @option{elf})
6583 This will first attempt a comparison using a CRC checksum, if this fails it will try a binary compare.
6587 @section Breakpoint and Watchpoint commands
6591 CPUs often make debug modules accessible through JTAG, with
6592 hardware support for a handful of code breakpoints and data
6594 In addition, CPUs almost always support software breakpoints.
6596 @deffn Command {bp} [address len [@option{hw}]]
6597 With no parameters, lists all active breakpoints.
6598 Else sets a breakpoint on code execution starting
6599 at @var{address} for @var{length} bytes.
6600 This is a software breakpoint, unless @option{hw} is specified
6601 in which case it will be a hardware breakpoint.
6603 (@xref{arm9vectorcatch,,arm9 vector_catch}, or @pxref{xscalevectorcatch,,xscale vector_catch},
6604 for similar mechanisms that do not consume hardware breakpoints.)
6607 @deffn Command {rbp} address
6608 Remove the breakpoint at @var{address}.
6611 @deffn Command {rwp} address
6612 Remove data watchpoint on @var{address}
6615 @deffn Command {wp} [address len [(@option{r}|@option{w}|@option{a}) [value [mask]]]]
6616 With no parameters, lists all active watchpoints.
6617 Else sets a data watchpoint on data from @var{address} for @var{length} bytes.
6618 The watch point is an "access" watchpoint unless
6619 the @option{r} or @option{w} parameter is provided,
6620 defining it as respectively a read or write watchpoint.
6621 If a @var{value} is provided, that value is used when determining if
6622 the watchpoint should trigger. The value may be first be masked
6623 using @var{mask} to mark ``don't care'' fields.
6626 @section Misc Commands
6629 @deffn Command {profile} seconds filename
6630 Profiling samples the CPU's program counter as quickly as possible,
6631 which is useful for non-intrusive stochastic profiling.
6632 Saves up to 10000 sampines in @file{filename} using ``gmon.out'' format.
6635 @deffn Command {version}
6636 Displays a string identifying the version of this OpenOCD server.
6639 @deffn Command {virt2phys} virtual_address
6640 Requests the current target to map the specified @var{virtual_address}
6641 to its corresponding physical address, and displays the result.
6644 @node Architecture and Core Commands
6645 @chapter Architecture and Core Commands
6646 @cindex Architecture Specific Commands
6647 @cindex Core Specific Commands
6649 Most CPUs have specialized JTAG operations to support debugging.
6650 OpenOCD packages most such operations in its standard command framework.
6651 Some of those operations don't fit well in that framework, so they are
6652 exposed here as architecture or implementation (core) specific commands.
6654 @anchor{armhardwaretracing}
6655 @section ARM Hardware Tracing
6660 CPUs based on ARM cores may include standard tracing interfaces,
6661 based on an ``Embedded Trace Module'' (ETM) which sends voluminous
6662 address and data bus trace records to a ``Trace Port''.
6666 Development-oriented boards will sometimes provide a high speed
6667 trace connector for collecting that data, when the particular CPU
6668 supports such an interface.
6669 (The standard connector is a 38-pin Mictor, with both JTAG
6670 and trace port support.)
6671 Those trace connectors are supported by higher end JTAG adapters
6672 and some logic analyzer modules; frequently those modules can
6673 buffer several megabytes of trace data.
6674 Configuring an ETM coupled to such an external trace port belongs
6675 in the board-specific configuration file.
6677 If the CPU doesn't provide an external interface, it probably
6678 has an ``Embedded Trace Buffer'' (ETB) on the chip, which is a
6679 dedicated SRAM. 4KBytes is one common ETB size.
6680 Configuring an ETM coupled only to an ETB belongs in the CPU-specific
6681 (target) configuration file, since it works the same on all boards.
6684 ETM support in OpenOCD doesn't seem to be widely used yet.
6687 ETM support may be buggy, and at least some @command{etm config}
6688 parameters should be detected by asking the ETM for them.
6690 ETM trigger events could also implement a kind of complex
6691 hardware breakpoint, much more powerful than the simple
6692 watchpoint hardware exported by EmbeddedICE modules.
6693 @emph{Such breakpoints can be triggered even when using the
6694 dummy trace port driver}.
6696 It seems like a GDB hookup should be possible,
6697 as well as tracing only during specific states
6698 (perhaps @emph{handling IRQ 23} or @emph{calls foo()}).
6700 There should be GUI tools to manipulate saved trace data and help
6701 analyse it in conjunction with the source code.
6702 It's unclear how much of a common interface is shared
6703 with the current XScale trace support, or should be
6704 shared with eventual Nexus-style trace module support.
6706 At this writing (November 2009) only ARM7, ARM9, and ARM11 support
6707 for ETM modules is available. The code should be able to
6708 work with some newer cores; but not all of them support
6709 this original style of JTAG access.
6712 @subsection ETM Configuration
6713 ETM setup is coupled with the trace port driver configuration.
6715 @deffn {Config Command} {etm config} target width mode clocking driver
6716 Declares the ETM associated with @var{target}, and associates it
6717 with a given trace port @var{driver}. @xref{traceportdrivers,,Trace Port Drivers}.
6719 Several of the parameters must reflect the trace port capabilities,
6720 which are a function of silicon capabilties (exposed later
6721 using @command{etm info}) and of what hardware is connected to
6722 that port (such as an external pod, or ETB).
6723 The @var{width} must be either 4, 8, or 16,
6724 except with ETMv3.0 and newer modules which may also
6725 support 1, 2, 24, 32, 48, and 64 bit widths.
6726 (With those versions, @command{etm info} also shows whether
6727 the selected port width and mode are supported.)
6729 The @var{mode} must be @option{normal}, @option{multiplexed},
6730 or @option{demultiplexed}.
6731 The @var{clocking} must be @option{half} or @option{full}.
6734 With ETMv3.0 and newer, the bits set with the @var{mode} and
6735 @var{clocking} parameters both control the mode.
6736 This modified mode does not map to the values supported by
6737 previous ETM modules, so this syntax is subject to change.
6741 You can see the ETM registers using the @command{reg} command.
6742 Not all possible registers are present in every ETM.
6743 Most of the registers are write-only, and are used to configure
6744 what CPU activities are traced.
6748 @deffn Command {etm info}
6749 Displays information about the current target's ETM.
6750 This includes resource counts from the @code{ETM_CONFIG} register,
6751 as well as silicon capabilities (except on rather old modules).
6752 from the @code{ETM_SYS_CONFIG} register.
6755 @deffn Command {etm status}
6756 Displays status of the current target's ETM and trace port driver:
6757 is the ETM idle, or is it collecting data?
6758 Did trace data overflow?
6762 @deffn Command {etm tracemode} [type context_id_bits cycle_accurate branch_output]
6763 Displays what data that ETM will collect.
6764 If arguments are provided, first configures that data.
6765 When the configuration changes, tracing is stopped
6766 and any buffered trace data is invalidated.
6769 @item @var{type} ... describing how data accesses are traced,
6770 when they pass any ViewData filtering that that was set up.
6772 @option{none} (save nothing),
6773 @option{data} (save data),
6774 @option{address} (save addresses),
6775 @option{all} (save data and addresses)
6776 @item @var{context_id_bits} ... 0, 8, 16, or 32
6777 @item @var{cycle_accurate} ... @option{enable} or @option{disable}
6778 cycle-accurate instruction tracing.
6779 Before ETMv3, enabling this causes much extra data to be recorded.
6780 @item @var{branch_output} ... @option{enable} or @option{disable}.
6781 Disable this unless you need to try reconstructing the instruction
6782 trace stream without an image of the code.
6786 @deffn Command {etm trigger_debug} (@option{enable}|@option{disable})
6787 Displays whether ETM triggering debug entry (like a breakpoint) is
6788 enabled or disabled, after optionally modifying that configuration.
6789 The default behaviour is @option{disable}.
6790 Any change takes effect after the next @command{etm start}.
6792 By using script commands to configure ETM registers, you can make the
6793 processor enter debug state automatically when certain conditions,
6794 more complex than supported by the breakpoint hardware, happen.
6797 @subsection ETM Trace Operation
6799 After setting up the ETM, you can use it to collect data.
6800 That data can be exported to files for later analysis.
6801 It can also be parsed with OpenOCD, for basic sanity checking.
6803 To configure what is being traced, you will need to write
6804 various trace registers using @command{reg ETM_*} commands.
6805 For the definitions of these registers, read ARM publication
6806 @emph{IHI 0014, ``Embedded Trace Macrocell, Architecture Specification''}.
6807 Be aware that most of the relevant registers are write-only,
6808 and that ETM resources are limited. There are only a handful
6809 of address comparators, data comparators, counters, and so on.
6811 Examples of scenarios you might arrange to trace include:
6814 @item Code flow within a function, @emph{excluding} subroutines
6815 it calls. Use address range comparators to enable tracing
6816 for instruction access within that function's body.
6817 @item Code flow within a function, @emph{including} subroutines
6818 it calls. Use the sequencer and address comparators to activate
6819 tracing on an ``entered function'' state, then deactivate it by
6820 exiting that state when the function's exit code is invoked.
6821 @item Code flow starting at the fifth invocation of a function,
6822 combining one of the above models with a counter.
6823 @item CPU data accesses to the registers for a particular device,
6824 using address range comparators and the ViewData logic.
6825 @item Such data accesses only during IRQ handling, combining the above
6826 model with sequencer triggers which on entry and exit to the IRQ handler.
6827 @item @emph{... more}
6830 At this writing, September 2009, there are no Tcl utility
6831 procedures to help set up any common tracing scenarios.
6833 @deffn Command {etm analyze}
6834 Reads trace data into memory, if it wasn't already present.
6835 Decodes and prints the data that was collected.
6838 @deffn Command {etm dump} filename
6839 Stores the captured trace data in @file{filename}.
6842 @deffn Command {etm image} filename [base_address] [type]
6843 Opens an image file.
6846 @deffn Command {etm load} filename
6847 Loads captured trace data from @file{filename}.
6850 @deffn Command {etm start}
6851 Starts trace data collection.
6854 @deffn Command {etm stop}
6855 Stops trace data collection.
6858 @anchor{traceportdrivers}
6859 @subsection Trace Port Drivers
6861 To use an ETM trace port it must be associated with a driver.
6863 @deffn {Trace Port Driver} dummy
6864 Use the @option{dummy} driver if you are configuring an ETM that's
6865 not connected to anything (on-chip ETB or off-chip trace connector).
6866 @emph{This driver lets OpenOCD talk to the ETM, but it does not expose
6867 any trace data collection.}
6868 @deffn {Config Command} {etm_dummy config} target
6869 Associates the ETM for @var{target} with a dummy driver.
6873 @deffn {Trace Port Driver} etb
6874 Use the @option{etb} driver if you are configuring an ETM
6875 to use on-chip ETB memory.
6876 @deffn {Config Command} {etb config} target etb_tap
6877 Associates the ETM for @var{target} with the ETB at @var{etb_tap}.
6878 You can see the ETB registers using the @command{reg} command.
6880 @deffn Command {etb trigger_percent} [percent]
6881 This displays, or optionally changes, ETB behavior after the
6882 ETM's configured @emph{trigger} event fires.
6883 It controls how much more trace data is saved after the (single)
6884 trace trigger becomes active.
6887 @item The default corresponds to @emph{trace around} usage,
6888 recording 50 percent data before the event and the rest
6890 @item The minimum value of @var{percent} is 2 percent,
6891 recording almost exclusively data before the trigger.
6892 Such extreme @emph{trace before} usage can help figure out
6893 what caused that event to happen.
6894 @item The maximum value of @var{percent} is 100 percent,
6895 recording data almost exclusively after the event.
6896 This extreme @emph{trace after} usage might help sort out
6897 how the event caused trouble.
6899 @c REVISIT allow "break" too -- enter debug mode.
6904 @deffn {Trace Port Driver} oocd_trace
6905 This driver isn't available unless OpenOCD was explicitly configured
6906 with the @option{--enable-oocd_trace} option. You probably don't want
6907 to configure it unless you've built the appropriate prototype hardware;
6908 it's @emph{proof-of-concept} software.
6910 Use the @option{oocd_trace} driver if you are configuring an ETM that's
6911 connected to an off-chip trace connector.
6913 @deffn {Config Command} {oocd_trace config} target tty
6914 Associates the ETM for @var{target} with a trace driver which
6915 collects data through the serial port @var{tty}.
6918 @deffn Command {oocd_trace resync}
6919 Re-synchronizes with the capture clock.
6922 @deffn Command {oocd_trace status}
6923 Reports whether the capture clock is locked or not.
6928 @section Generic ARM
6931 These commands should be available on all ARM processors.
6932 They are available in addition to other core-specific
6933 commands that may be available.
6935 @deffn Command {arm core_state} [@option{arm}|@option{thumb}]
6936 Displays the core_state, optionally changing it to process
6937 either @option{arm} or @option{thumb} instructions.
6938 The target may later be resumed in the currently set core_state.
6939 (Processors may also support the Jazelle state, but
6940 that is not currently supported in OpenOCD.)
6943 @deffn Command {arm disassemble} address [count [@option{thumb}]]
6945 Disassembles @var{count} instructions starting at @var{address}.
6946 If @var{count} is not specified, a single instruction is disassembled.
6947 If @option{thumb} is specified, or the low bit of the address is set,
6948 Thumb2 (mixed 16/32-bit) instructions are used;
6949 else ARM (32-bit) instructions are used.
6950 (Processors may also support the Jazelle state, but
6951 those instructions are not currently understood by OpenOCD.)
6953 Note that all Thumb instructions are Thumb2 instructions,
6954 so older processors (without Thumb2 support) will still
6955 see correct disassembly of Thumb code.
6956 Also, ThumbEE opcodes are the same as Thumb2,
6957 with a handful of exceptions.
6958 ThumbEE disassembly currently has no explicit support.
6961 @deffn Command {arm mcr} pX op1 CRn CRm op2 value
6962 Write @var{value} to a coprocessor @var{pX} register
6963 passing parameters @var{CRn},
6964 @var{CRm}, opcodes @var{opc1} and @var{opc2},
6965 and using the MCR instruction.
6966 (Parameter sequence matches the ARM instruction, but omits
6970 @deffn Command {arm mrc} pX coproc op1 CRn CRm op2
6971 Read a coprocessor @var{pX} register passing parameters @var{CRn},
6972 @var{CRm}, opcodes @var{opc1} and @var{opc2},
6973 and the MRC instruction.
6974 Returns the result so it can be manipulated by Jim scripts.
6975 (Parameter sequence matches the ARM instruction, but omits
6979 @deffn Command {arm reg}
6980 Display a table of all banked core registers, fetching the current value from every
6981 core mode if necessary.
6984 @deffn Command {arm semihosting} [@option{enable}|@option{disable}]
6985 @cindex ARM semihosting
6986 Display status of semihosting, after optionally changing that status.
6988 Semihosting allows for code executing on an ARM target to use the
6989 I/O facilities on the host computer i.e. the system where OpenOCD
6990 is running. The target application must be linked against a library
6991 implementing the ARM semihosting convention that forwards operation
6992 requests by using a special SVC instruction that is trapped at the
6993 Supervisor Call vector by OpenOCD.
6996 @section ARMv4 and ARMv5 Architecture
7000 The ARMv4 and ARMv5 architectures are widely used in embedded systems,
7001 and introduced core parts of the instruction set in use today.
7002 That includes the Thumb instruction set, introduced in the ARMv4T
7005 @subsection ARM7 and ARM9 specific commands
7009 These commands are specific to ARM7 and ARM9 cores, like ARM7TDMI, ARM720T,
7010 ARM9TDMI, ARM920T or ARM926EJ-S.
7011 They are available in addition to the ARM commands,
7012 and any other core-specific commands that may be available.
7014 @deffn Command {arm7_9 dbgrq} [@option{enable}|@option{disable}]
7015 Displays the value of the flag controlling use of the
7016 the EmbeddedIce DBGRQ signal to force entry into debug mode,
7017 instead of breakpoints.
7018 If a boolean parameter is provided, first assigns that flag.
7021 safe for all but ARM7TDMI-S cores (like NXP LPC).
7022 This feature is enabled by default on most ARM9 cores,
7023 including ARM9TDMI, ARM920T, and ARM926EJ-S.
7026 @deffn Command {arm7_9 dcc_downloads} [@option{enable}|@option{disable}]
7028 Displays the value of the flag controlling use of the debug communications
7029 channel (DCC) to write larger (>128 byte) amounts of memory.
7030 If a boolean parameter is provided, first assigns that flag.
7032 DCC downloads offer a huge speed increase, but might be
7033 unsafe, especially with targets running at very low speeds. This command was introduced
7034 with OpenOCD rev. 60, and requires a few bytes of working area.
7037 @deffn Command {arm7_9 fast_memory_access} [@option{enable}|@option{disable}]
7038 Displays the value of the flag controlling use of memory writes and reads
7039 that don't check completion of the operation.
7040 If a boolean parameter is provided, first assigns that flag.
7042 This provides a huge speed increase, especially with USB JTAG
7043 cables (FT2232), but might be unsafe if used with targets running at very low
7044 speeds, like the 32kHz startup clock of an AT91RM9200.
7047 @subsection ARM720T specific commands
7050 These commands are available to ARM720T based CPUs,
7051 which are implementations of the ARMv4T architecture
7052 based on the ARM7TDMI-S integer core.
7053 They are available in addition to the ARM and ARM7/ARM9 commands.
7055 @deffn Command {arm720t cp15} opcode [value]
7056 @emph{DEPRECATED -- avoid using this.
7057 Use the @command{arm mrc} or @command{arm mcr} commands instead.}
7059 Display cp15 register returned by the ARM instruction @var{opcode};
7060 else if a @var{value} is provided, that value is written to that register.
7061 The @var{opcode} should be the value of either an MRC or MCR instruction.
7064 @subsection ARM9 specific commands
7067 ARM9-family cores are built around ARM9TDMI or ARM9E (including ARM9EJS)
7069 Such cores include the ARM920T, ARM926EJ-S, and ARM966.
7071 @c 9-june-2009: tried this on arm920t, it didn't work.
7072 @c no-params always lists nothing caught, and that's how it acts.
7073 @c 23-oct-2009: doesn't work _consistently_ ... as if the ICE
7074 @c versions have different rules about when they commit writes.
7076 @anchor{arm9vectorcatch}
7077 @deffn Command {arm9 vector_catch} [@option{all}|@option{none}|list]
7078 @cindex vector_catch
7079 Vector Catch hardware provides a sort of dedicated breakpoint
7080 for hardware events such as reset, interrupt, and abort.
7081 You can use this to conserve normal breakpoint resources,
7082 so long as you're not concerned with code that branches directly
7083 to those hardware vectors.
7085 This always finishes by listing the current configuration.
7086 If parameters are provided, it first reconfigures the
7087 vector catch hardware to intercept
7088 @option{all} of the hardware vectors,
7089 @option{none} of them,
7090 or a list with one or more of the following:
7091 @option{reset} @option{undef} @option{swi} @option{pabt} @option{dabt}
7092 @option{irq} @option{fiq}.
7095 @subsection ARM920T specific commands
7098 These commands are available to ARM920T based CPUs,
7099 which are implementations of the ARMv4T architecture
7100 built using the ARM9TDMI integer core.
7101 They are available in addition to the ARM, ARM7/ARM9,
7104 @deffn Command {arm920t cache_info}
7105 Print information about the caches found. This allows to see whether your target
7106 is an ARM920T (2x16kByte cache) or ARM922T (2x8kByte cache).
7109 @deffn Command {arm920t cp15} regnum [value]
7110 Display cp15 register @var{regnum};
7111 else if a @var{value} is provided, that value is written to that register.
7112 This uses "physical access" and the register number is as
7113 shown in bits 38..33 of table 9-9 in the ARM920T TRM.
7114 (Not all registers can be written.)
7117 @deffn Command {arm920t cp15i} opcode [value [address]]
7118 @emph{DEPRECATED -- avoid using this.
7119 Use the @command{arm mrc} or @command{arm mcr} commands instead.}
7121 Interpreted access using ARM instruction @var{opcode}, which should
7122 be the value of either an MRC or MCR instruction
7123 (as shown tables 9-11, 9-12, and 9-13 in the ARM920T TRM).
7124 If no @var{value} is provided, the result is displayed.
7125 Else if that value is written using the specified @var{address},
7126 or using zero if no other address is provided.
7129 @deffn Command {arm920t read_cache} filename
7130 Dump the content of ICache and DCache to a file named @file{filename}.
7133 @deffn Command {arm920t read_mmu} filename
7134 Dump the content of the ITLB and DTLB to a file named @file{filename}.
7137 @subsection ARM926ej-s specific commands
7140 These commands are available to ARM926ej-s based CPUs,
7141 which are implementations of the ARMv5TEJ architecture
7142 based on the ARM9EJ-S integer core.
7143 They are available in addition to the ARM, ARM7/ARM9,
7146 The Feroceon cores also support these commands, although
7147 they are not built from ARM926ej-s designs.
7149 @deffn Command {arm926ejs cache_info}
7150 Print information about the caches found.
7153 @subsection ARM966E specific commands
7156 These commands are available to ARM966 based CPUs,
7157 which are implementations of the ARMv5TE architecture.
7158 They are available in addition to the ARM, ARM7/ARM9,
7161 @deffn Command {arm966e cp15} regnum [value]
7162 Display cp15 register @var{regnum};
7163 else if a @var{value} is provided, that value is written to that register.
7164 The six bit @var{regnum} values are bits 37..32 from table 7-2 of the
7166 There is no current control over bits 31..30 from that table,
7167 as required for BIST support.
7170 @subsection XScale specific commands
7173 Some notes about the debug implementation on the XScale CPUs:
7175 The XScale CPU provides a special debug-only mini-instruction cache
7176 (mini-IC) in which exception vectors and target-resident debug handler
7177 code are placed by OpenOCD. In order to get access to the CPU, OpenOCD
7178 must point vector 0 (the reset vector) to the entry of the debug
7179 handler. However, this means that the complete first cacheline in the
7180 mini-IC is marked valid, which makes the CPU fetch all exception
7181 handlers from the mini-IC, ignoring the code in RAM.
7183 To address this situation, OpenOCD provides the @code{xscale
7184 vector_table} command, which allows the user to explicity write
7185 individual entries to either the high or low vector table stored in
7188 It is recommended to place a pc-relative indirect branch in the vector
7189 table, and put the branch destination somewhere in memory. Doing so
7190 makes sure the code in the vector table stays constant regardless of
7191 code layout in memory:
7194 ldr pc,[pc,#0x100-8]
7195 ldr pc,[pc,#0x100-8]
7196 ldr pc,[pc,#0x100-8]
7197 ldr pc,[pc,#0x100-8]
7198 ldr pc,[pc,#0x100-8]
7199 ldr pc,[pc,#0x100-8]
7200 ldr pc,[pc,#0x100-8]
7201 ldr pc,[pc,#0x100-8]
7203 .long real_reset_vector
7204 .long real_ui_handler
7205 .long real_swi_handler
7207 .long real_data_abort
7208 .long 0 /* unused */
7209 .long real_irq_handler
7210 .long real_fiq_handler
7213 Alternatively, you may choose to keep some or all of the mini-IC
7214 vector table entries synced with those written to memory by your
7215 system software. The mini-IC can not be modified while the processor
7216 is executing, but for each vector table entry not previously defined
7217 using the @code{xscale vector_table} command, OpenOCD will copy the
7218 value from memory to the mini-IC every time execution resumes from a
7219 halt. This is done for both high and low vector tables (although the
7220 table not in use may not be mapped to valid memory, and in this case
7221 that copy operation will silently fail). This means that you will
7222 need to briefly halt execution at some strategic point during system
7223 start-up; e.g., after the software has initialized the vector table,
7224 but before exceptions are enabled. A breakpoint can be used to
7225 accomplish this once the appropriate location in the start-up code has
7226 been identified. A watchpoint over the vector table region is helpful
7227 in finding the location if you're not sure. Note that the same
7228 situation exists any time the vector table is modified by the system
7231 The debug handler must be placed somewhere in the address space using
7232 the @code{xscale debug_handler} command. The allowed locations for the
7233 debug handler are either (0x800 - 0x1fef800) or (0xfe000800 -
7234 0xfffff800). The default value is 0xfe000800.
7236 XScale has resources to support two hardware breakpoints and two
7237 watchpoints. However, the following restrictions on watchpoint
7238 functionality apply: (1) the value and mask arguments to the @code{wp}
7239 command are not supported, (2) the watchpoint length must be a
7240 power of two and not less than four, and can not be greater than the
7241 watchpoint address, and (3) a watchpoint with a length greater than
7242 four consumes all the watchpoint hardware resources. This means that
7243 at any one time, you can have enabled either two watchpoints with a
7244 length of four, or one watchpoint with a length greater than four.
7246 These commands are available to XScale based CPUs,
7247 which are implementations of the ARMv5TE architecture.
7249 @deffn Command {xscale analyze_trace}
7250 Displays the contents of the trace buffer.
7253 @deffn Command {xscale cache_clean_address} address
7254 Changes the address used when cleaning the data cache.
7257 @deffn Command {xscale cache_info}
7258 Displays information about the CPU caches.
7261 @deffn Command {xscale cp15} regnum [value]
7262 Display cp15 register @var{regnum};
7263 else if a @var{value} is provided, that value is written to that register.
7266 @deffn Command {xscale debug_handler} target address
7267 Changes the address used for the specified target's debug handler.
7270 @deffn Command {xscale dcache} [@option{enable}|@option{disable}]
7271 Enables or disable the CPU's data cache.
7274 @deffn Command {xscale dump_trace} filename
7275 Dumps the raw contents of the trace buffer to @file{filename}.
7278 @deffn Command {xscale icache} [@option{enable}|@option{disable}]
7279 Enables or disable the CPU's instruction cache.
7282 @deffn Command {xscale mmu} [@option{enable}|@option{disable}]
7283 Enables or disable the CPU's memory management unit.
7286 @deffn Command {xscale trace_buffer} [@option{enable}|@option{disable} [@option{fill} [n] | @option{wrap}]]
7287 Displays the trace buffer status, after optionally
7288 enabling or disabling the trace buffer
7289 and modifying how it is emptied.
7292 @deffn Command {xscale trace_image} filename [offset [type]]
7293 Opens a trace image from @file{filename}, optionally rebasing
7294 its segment addresses by @var{offset}.
7295 The image @var{type} may be one of
7296 @option{bin} (binary), @option{ihex} (Intel hex),
7297 @option{elf} (ELF file), @option{s19} (Motorola s19),
7298 @option{mem}, or @option{builder}.
7301 @anchor{xscalevectorcatch}
7302 @deffn Command {xscale vector_catch} [mask]
7303 @cindex vector_catch
7304 Display a bitmask showing the hardware vectors to catch.
7305 If the optional parameter is provided, first set the bitmask to that value.
7307 The mask bits correspond with bit 16..23 in the DCSR:
7310 0x02 Trap Undefined Instructions
7311 0x04 Trap Software Interrupt
7312 0x08 Trap Prefetch Abort
7313 0x10 Trap Data Abort
7320 @deffn Command {xscale vector_table} [(@option{low}|@option{high}) index value]
7321 @cindex vector_table
7323 Set an entry in the mini-IC vector table. There are two tables: one for
7324 low vectors (at 0x00000000), and one for high vectors (0xFFFF0000), each
7325 holding the 8 exception vectors. @var{index} can be 1-7, because vector 0
7326 points to the debug handler entry and can not be overwritten.
7327 @var{value} holds the 32-bit opcode that is placed in the mini-IC.
7329 Without arguments, the current settings are displayed.
7333 @section ARMv6 Architecture
7336 @subsection ARM11 specific commands
7339 @deffn Command {arm11 memwrite burst} [@option{enable}|@option{disable}]
7340 Displays the value of the memwrite burst-enable flag,
7341 which is enabled by default.
7342 If a boolean parameter is provided, first assigns that flag.
7343 Burst writes are only used for memory writes larger than 1 word.
7344 They improve performance by assuming that the CPU has read each data
7345 word over JTAG and completed its write before the next word arrives,
7346 instead of polling for a status flag to verify that completion.
7347 This is usually safe, because JTAG runs much slower than the CPU.
7350 @deffn Command {arm11 memwrite error_fatal} [@option{enable}|@option{disable}]
7351 Displays the value of the memwrite error_fatal flag,
7352 which is enabled by default.
7353 If a boolean parameter is provided, first assigns that flag.
7354 When set, certain memory write errors cause earlier transfer termination.
7357 @deffn Command {arm11 step_irq_enable} [@option{enable}|@option{disable}]
7358 Displays the value of the flag controlling whether
7359 IRQs are enabled during single stepping;
7360 they are disabled by default.
7361 If a boolean parameter is provided, first assigns that.
7364 @deffn Command {arm11 vcr} [value]
7365 @cindex vector_catch
7366 Displays the value of the @emph{Vector Catch Register (VCR)},
7367 coprocessor 14 register 7.
7368 If @var{value} is defined, first assigns that.
7370 Vector Catch hardware provides dedicated breakpoints
7371 for certain hardware events.
7372 The specific bit values are core-specific (as in fact is using
7373 coprocessor 14 register 7 itself) but all current ARM11
7374 cores @emph{except the ARM1176} use the same six bits.
7377 @section ARMv7 Architecture
7380 @subsection ARMv7 Debug Access Port (DAP) specific commands
7381 @cindex Debug Access Port
7383 These commands are specific to ARM architecture v7 Debug Access Port (DAP),
7384 included on Cortex-M and Cortex-A systems.
7385 They are available in addition to other core-specific commands that may be available.
7387 @deffn Command {dap apid} [num]
7388 Displays ID register from AP @var{num},
7389 defaulting to the currently selected AP.
7392 @deffn Command {dap apsel} [num]
7393 Select AP @var{num}, defaulting to 0.
7396 @deffn Command {dap baseaddr} [num]
7397 Displays debug base address from MEM-AP @var{num},
7398 defaulting to the currently selected AP.
7401 @deffn Command {dap info} [num]
7402 Displays the ROM table for MEM-AP @var{num},
7403 defaulting to the currently selected AP.
7406 @deffn Command {dap memaccess} [value]
7407 Displays the number of extra tck cycles in the JTAG idle to use for MEM-AP
7408 memory bus access [0-255], giving additional time to respond to reads.
7409 If @var{value} is defined, first assigns that.
7412 @deffn Command {dap apcsw} [0 / 1]
7413 fix CSW_SPROT from register AP_REG_CSW on selected dap.
7417 @subsection Cortex-M specific commands
7420 @deffn Command {cortex_m maskisr} (@option{auto}|@option{on}|@option{off})
7421 Control masking (disabling) interrupts during target step/resume.
7423 The @option{auto} option handles interrupts during stepping a way they get
7424 served but don't disturb the program flow. The step command first allows
7425 pending interrupt handlers to execute, then disables interrupts and steps over
7426 the next instruction where the core was halted. After the step interrupts
7427 are enabled again. If the interrupt handlers don't complete within 500ms,
7428 the step command leaves with the core running.
7430 Note that a free breakpoint is required for the @option{auto} option. If no
7431 breakpoint is available at the time of the step, then the step is taken
7432 with interrupts enabled, i.e. the same way the @option{off} option does.
7434 Default is @option{auto}.
7437 @deffn Command {cortex_m vector_catch} [@option{all}|@option{none}|list]
7438 @cindex vector_catch
7439 Vector Catch hardware provides dedicated breakpoints
7440 for certain hardware events.
7442 Parameters request interception of
7443 @option{all} of these hardware event vectors,
7444 @option{none} of them,
7445 or one or more of the following:
7446 @option{hard_err} for a HardFault exception;
7447 @option{mm_err} for a MemManage exception;
7448 @option{bus_err} for a BusFault exception;
7451 @option{chk_err}, or
7452 @option{nocp_err} for various UsageFault exceptions; or
7454 If NVIC setup code does not enable them,
7455 MemManage, BusFault, and UsageFault exceptions
7456 are mapped to HardFault.
7457 UsageFault checks for
7458 divide-by-zero and unaligned access
7459 must also be explicitly enabled.
7461 This finishes by listing the current vector catch configuration.
7464 @deffn Command {cortex_m reset_config} (@option{srst}|@option{sysresetreq}|@option{vectreset})
7465 Control reset handling. The default @option{srst} is to use srst if fitted,
7466 otherwise fallback to @option{vectreset}.
7468 @item @option{srst} use hardware srst if fitted otherwise fallback to @option{vectreset}.
7469 @item @option{sysresetreq} use NVIC SYSRESETREQ to reset system.
7470 @item @option{vectreset} use NVIC VECTRESET to reset system.
7472 Using @option{vectreset} is a safe option for all current Cortex-M cores.
7473 This however has the disadvantage of only resetting the core, all peripherals
7474 are uneffected. A solution would be to use a @code{reset-init} event handler to manually reset
7476 @xref{targetevents,,Target Events}.
7479 @anchor{softwaredebugmessagesandtracing}
7480 @section Software Debug Messages and Tracing
7481 @cindex Linux-ARM DCC support
7485 OpenOCD can process certain requests from target software, when
7486 the target uses appropriate libraries.
7487 The most powerful mechanism is semihosting, but there is also
7488 a lighter weight mechanism using only the DCC channel.
7490 Currently @command{target_request debugmsgs}
7491 is supported only for @option{arm7_9} and @option{cortex_m} cores.
7492 These messages are received as part of target polling, so
7493 you need to have @command{poll on} active to receive them.
7494 They are intrusive in that they will affect program execution
7495 times. If that is a problem, @pxref{armhardwaretracing,,ARM Hardware Tracing}.
7497 See @file{libdcc} in the contrib dir for more details.
7498 In addition to sending strings, characters, and
7499 arrays of various size integers from the target,
7500 @file{libdcc} also exports a software trace point mechanism.
7501 The target being debugged may
7502 issue trace messages which include a 24-bit @dfn{trace point} number.
7503 Trace point support includes two distinct mechanisms,
7504 each supported by a command:
7507 @item @emph{History} ... A circular buffer of trace points
7508 can be set up, and then displayed at any time.
7509 This tracks where code has been, which can be invaluable in
7510 finding out how some fault was triggered.
7512 The buffer may overflow, since it collects records continuously.
7513 It may be useful to use some of the 24 bits to represent a
7514 particular event, and other bits to hold data.
7516 @item @emph{Counting} ... An array of counters can be set up,
7517 and then displayed at any time.
7518 This can help establish code coverage and identify hot spots.
7520 The array of counters is directly indexed by the trace point
7521 number, so trace points with higher numbers are not counted.
7524 Linux-ARM kernels have a ``Kernel low-level debugging
7525 via EmbeddedICE DCC channel'' option (CONFIG_DEBUG_ICEDCC,
7526 depends on CONFIG_DEBUG_LL) which uses this mechanism to
7527 deliver messages before a serial console can be activated.
7528 This is not the same format used by @file{libdcc}.
7529 Other software, such as the U-Boot boot loader, sometimes
7530 does the same thing.
7532 @deffn Command {target_request debugmsgs} [@option{enable}|@option{disable}|@option{charmsg}]
7533 Displays current handling of target DCC message requests.
7534 These messages may be sent to the debugger while the target is running.
7535 The optional @option{enable} and @option{charmsg} parameters
7536 both enable the messages, while @option{disable} disables them.
7538 With @option{charmsg} the DCC words each contain one character,
7539 as used by Linux with CONFIG_DEBUG_ICEDCC;
7540 otherwise the libdcc format is used.
7543 @deffn Command {trace history} [@option{clear}|count]
7544 With no parameter, displays all the trace points that have triggered
7545 in the order they triggered.
7546 With the parameter @option{clear}, erases all current trace history records.
7547 With a @var{count} parameter, allocates space for that many
7551 @deffn Command {trace point} [@option{clear}|identifier]
7552 With no parameter, displays all trace point identifiers and how many times
7553 they have been triggered.
7554 With the parameter @option{clear}, erases all current trace point counters.
7555 With a numeric @var{identifier} parameter, creates a new a trace point counter
7556 and associates it with that identifier.
7558 @emph{Important:} The identifier and the trace point number
7559 are not related except by this command.
7560 These trace point numbers always start at zero (from server startup,
7561 or after @command{trace point clear}) and count up from there.
7566 @chapter JTAG Commands
7567 @cindex JTAG Commands
7568 Most general purpose JTAG commands have been presented earlier.
7569 (@xref{jtagspeed,,JTAG Speed}, @ref{Reset Configuration}, and @ref{TAP Declaration}.)
7570 Lower level JTAG commands, as presented here,
7571 may be needed to work with targets which require special
7572 attention during operations such as reset or initialization.
7574 To use these commands you will need to understand some
7575 of the basics of JTAG, including:
7578 @item A JTAG scan chain consists of a sequence of individual TAP
7579 devices such as a CPUs.
7580 @item Control operations involve moving each TAP through the same
7581 standard state machine (in parallel)
7582 using their shared TMS and clock signals.
7583 @item Data transfer involves shifting data through the chain of
7584 instruction or data registers of each TAP, writing new register values
7585 while the reading previous ones.
7586 @item Data register sizes are a function of the instruction active in
7587 a given TAP, while instruction register sizes are fixed for each TAP.
7588 All TAPs support a BYPASS instruction with a single bit data register.
7589 @item The way OpenOCD differentiates between TAP devices is by
7590 shifting different instructions into (and out of) their instruction
7594 @section Low Level JTAG Commands
7596 These commands are used by developers who need to access
7597 JTAG instruction or data registers, possibly controlling
7598 the order of TAP state transitions.
7599 If you're not debugging OpenOCD internals, or bringing up a
7600 new JTAG adapter or a new type of TAP device (like a CPU or
7601 JTAG router), you probably won't need to use these commands.
7602 In a debug session that doesn't use JTAG for its transport protocol,
7603 these commands are not available.
7605 @deffn Command {drscan} tap [numbits value]+ [@option{-endstate} tap_state]
7606 Loads the data register of @var{tap} with a series of bit fields
7607 that specify the entire register.
7608 Each field is @var{numbits} bits long with
7609 a numeric @var{value} (hexadecimal encouraged).
7610 The return value holds the original value of each
7613 For example, a 38 bit number might be specified as one
7614 field of 32 bits then one of 6 bits.
7615 @emph{For portability, never pass fields which are more
7616 than 32 bits long. Many OpenOCD implementations do not
7617 support 64-bit (or larger) integer values.}
7619 All TAPs other than @var{tap} must be in BYPASS mode.
7620 The single bit in their data registers does not matter.
7622 When @var{tap_state} is specified, the JTAG state machine is left
7624 For example @sc{drpause} might be specified, so that more
7625 instructions can be issued before re-entering the @sc{run/idle} state.
7626 If the end state is not specified, the @sc{run/idle} state is entered.
7629 OpenOCD does not record information about data register lengths,
7630 so @emph{it is important that you get the bit field lengths right}.
7631 Remember that different JTAG instructions refer to different
7632 data registers, which may have different lengths.
7633 Moreover, those lengths may not be fixed;
7634 the SCAN_N instruction can change the length of
7635 the register accessed by the INTEST instruction
7636 (by connecting a different scan chain).
7640 @deffn Command {flush_count}
7641 Returns the number of times the JTAG queue has been flushed.
7642 This may be used for performance tuning.
7644 For example, flushing a queue over USB involves a
7645 minimum latency, often several milliseconds, which does
7646 not change with the amount of data which is written.
7647 You may be able to identify performance problems by finding
7648 tasks which waste bandwidth by flushing small transfers too often,
7649 instead of batching them into larger operations.
7652 @deffn Command {irscan} [tap instruction]+ [@option{-endstate} tap_state]
7653 For each @var{tap} listed, loads the instruction register
7654 with its associated numeric @var{instruction}.
7655 (The number of bits in that instruction may be displayed
7656 using the @command{scan_chain} command.)
7657 For other TAPs, a BYPASS instruction is loaded.
7659 When @var{tap_state} is specified, the JTAG state machine is left
7661 For example @sc{irpause} might be specified, so the data register
7662 can be loaded before re-entering the @sc{run/idle} state.
7663 If the end state is not specified, the @sc{run/idle} state is entered.
7666 OpenOCD currently supports only a single field for instruction
7667 register values, unlike data register values.
7668 For TAPs where the instruction register length is more than 32 bits,
7669 portable scripts currently must issue only BYPASS instructions.
7673 @deffn Command {jtag_reset} trst srst
7674 Set values of reset signals.
7675 The @var{trst} and @var{srst} parameter values may be
7676 @option{0}, indicating that reset is inactive (pulled or driven high),
7677 or @option{1}, indicating it is active (pulled or driven low).
7678 The @command{reset_config} command should already have been used
7679 to configure how the board and JTAG adapter treat these two
7680 signals, and to say if either signal is even present.
7681 @xref{Reset Configuration}.
7683 Note that TRST is specially handled.
7684 It actually signifies JTAG's @sc{reset} state.
7685 So if the board doesn't support the optional TRST signal,
7686 or it doesn't support it along with the specified SRST value,
7687 JTAG reset is triggered with TMS and TCK signals
7688 instead of the TRST signal.
7689 And no matter how that JTAG reset is triggered, once
7690 the scan chain enters @sc{reset} with TRST inactive,
7691 TAP @code{post-reset} events are delivered to all TAPs
7692 with handlers for that event.
7695 @deffn Command {pathmove} start_state [next_state ...]
7696 Start by moving to @var{start_state}, which
7697 must be one of the @emph{stable} states.
7698 Unless it is the only state given, this will often be the
7699 current state, so that no TCK transitions are needed.
7700 Then, in a series of single state transitions
7701 (conforming to the JTAG state machine) shift to
7702 each @var{next_state} in sequence, one per TCK cycle.
7703 The final state must also be stable.
7706 @deffn Command {runtest} @var{num_cycles}
7707 Move to the @sc{run/idle} state, and execute at least
7708 @var{num_cycles} of the JTAG clock (TCK).
7709 Instructions often need some time
7710 to execute before they take effect.
7713 @c tms_sequence (short|long)
7714 @c ... temporary, debug-only, other than USBprog bug workaround...
7716 @deffn Command {verify_ircapture} (@option{enable}|@option{disable})
7717 Verify values captured during @sc{ircapture} and returned
7718 during IR scans. Default is enabled, but this can be
7719 overridden by @command{verify_jtag}.
7720 This flag is ignored when validating JTAG chain configuration.
7723 @deffn Command {verify_jtag} (@option{enable}|@option{disable})
7724 Enables verification of DR and IR scans, to help detect
7725 programming errors. For IR scans, @command{verify_ircapture}
7726 must also be enabled.
7730 @section TAP state names
7731 @cindex TAP state names
7733 The @var{tap_state} names used by OpenOCD in the @command{drscan},
7734 @command{irscan}, and @command{pathmove} commands are the same
7735 as those used in SVF boundary scan documents, except that
7736 SVF uses @sc{idle} instead of @sc{run/idle}.
7739 @item @b{RESET} ... @emph{stable} (with TMS high);
7740 acts as if TRST were pulsed
7741 @item @b{RUN/IDLE} ... @emph{stable}; don't assume this always means IDLE
7744 @item @b{DRSHIFT} ... @emph{stable}; TDI/TDO shifting
7745 through the data register
7747 @item @b{DRPAUSE} ... @emph{stable}; data register ready
7748 for update or more shifting
7753 @item @b{IRSHIFT} ... @emph{stable}; TDI/TDO shifting
7754 through the instruction register
7756 @item @b{IRPAUSE} ... @emph{stable}; instruction register ready
7757 for update or more shifting
7762 Note that only six of those states are fully ``stable'' in the
7763 face of TMS fixed (low except for @sc{reset})
7764 and a free-running JTAG clock. For all the
7765 others, the next TCK transition changes to a new state.
7768 @item From @sc{drshift} and @sc{irshift}, clock transitions will
7769 produce side effects by changing register contents. The values
7770 to be latched in upcoming @sc{drupdate} or @sc{irupdate} states
7771 may not be as expected.
7772 @item @sc{run/idle}, @sc{drpause}, and @sc{irpause} are reasonable
7773 choices after @command{drscan} or @command{irscan} commands,
7774 since they are free of JTAG side effects.
7775 @item @sc{run/idle} may have side effects that appear at non-JTAG
7776 levels, such as advancing the ARM9E-S instruction pipeline.
7777 Consult the documentation for the TAP(s) you are working with.
7780 @node Boundary Scan Commands
7781 @chapter Boundary Scan Commands
7783 One of the original purposes of JTAG was to support
7784 boundary scan based hardware testing.
7785 Although its primary focus is to support On-Chip Debugging,
7786 OpenOCD also includes some boundary scan commands.
7788 @section SVF: Serial Vector Format
7789 @cindex Serial Vector Format
7792 The Serial Vector Format, better known as @dfn{SVF}, is a
7793 way to represent JTAG test patterns in text files.
7794 In a debug session using JTAG for its transport protocol,
7795 OpenOCD supports running such test files.
7797 @deffn Command {svf} filename [@option{quiet}]
7798 This issues a JTAG reset (Test-Logic-Reset) and then
7799 runs the SVF script from @file{filename}.
7800 Unless the @option{quiet} option is specified,
7801 each command is logged before it is executed.
7804 @section XSVF: Xilinx Serial Vector Format
7805 @cindex Xilinx Serial Vector Format
7808 The Xilinx Serial Vector Format, better known as @dfn{XSVF}, is a
7809 binary representation of SVF which is optimized for use with
7811 In a debug session using JTAG for its transport protocol,
7812 OpenOCD supports running such test files.
7814 @quotation Important
7815 Not all XSVF commands are supported.
7818 @deffn Command {xsvf} (tapname|@option{plain}) filename [@option{virt2}] [@option{quiet}]
7819 This issues a JTAG reset (Test-Logic-Reset) and then
7820 runs the XSVF script from @file{filename}.
7821 When a @var{tapname} is specified, the commands are directed at
7823 When @option{virt2} is specified, the @sc{xruntest} command counts
7824 are interpreted as TCK cycles instead of microseconds.
7825 Unless the @option{quiet} option is specified,
7826 messages are logged for comments and some retries.
7829 The OpenOCD sources also include two utility scripts
7830 for working with XSVF; they are not currently installed
7831 after building the software.
7832 You may find them useful:
7835 @item @emph{svf2xsvf} ... converts SVF files into the extended XSVF
7836 syntax understood by the @command{xsvf} command; see notes below.
7837 @item @emph{xsvfdump} ... converts XSVF files into a text output format;
7838 understands the OpenOCD extensions.
7841 The input format accepts a handful of non-standard extensions.
7842 These include three opcodes corresponding to SVF extensions
7843 from Lattice Semiconductor (LCOUNT, LDELAY, LDSR), and
7844 two opcodes supporting a more accurate translation of SVF
7845 (XTRST, XWAITSTATE).
7846 If @emph{xsvfdump} shows a file is using those opcodes, it
7847 probably will not be usable with other XSVF tools.
7853 If OpenOCD runs on an embedded host(as ZY1000 does), then TFTP can
7854 be used to access files on PCs (either the developer's PC or some other PC).
7856 The way this works on the ZY1000 is to prefix a filename by
7857 "/tftp/ip/" and append the TFTP path on the TFTP
7858 server (tftpd). For example,
7861 load_image /tftp/10.0.0.96/c:\temp\abc.elf
7864 will load c:\temp\abc.elf from the developer pc (10.0.0.96) into memory as
7865 if the file was hosted on the embedded host.
7867 In order to achieve decent performance, you must choose a TFTP server
7868 that supports a packet size bigger than the default packet size (512 bytes). There
7869 are numerous TFTP servers out there (free and commercial) and you will have to do
7870 a bit of googling to find something that fits your requirements.
7872 @node GDB and OpenOCD
7873 @chapter GDB and OpenOCD
7875 OpenOCD complies with the remote gdbserver protocol, and as such can be used
7876 to debug remote targets.
7877 Setting up GDB to work with OpenOCD can involve several components:
7880 @item The OpenOCD server support for GDB may need to be configured.
7881 @xref{gdbconfiguration,,GDB Configuration}.
7882 @item GDB's support for OpenOCD may need configuration,
7883 as shown in this chapter.
7884 @item If you have a GUI environment like Eclipse,
7885 that also will probably need to be configured.
7888 Of course, the version of GDB you use will need to be one which has
7889 been built to know about the target CPU you're using. It's probably
7890 part of the tool chain you're using. For example, if you are doing
7891 cross-development for ARM on an x86 PC, instead of using the native
7892 x86 @command{gdb} command you might use @command{arm-none-eabi-gdb}
7893 if that's the tool chain used to compile your code.
7895 @section Connecting to GDB
7896 @cindex Connecting to GDB
7897 Use GDB 6.7 or newer with OpenOCD if you run into trouble. For
7898 instance GDB 6.3 has a known bug that produces bogus memory access
7899 errors, which has since been fixed; see
7900 @url{http://osdir.com/ml/gdb.bugs.discuss/2004-12/msg00018.html}
7902 OpenOCD can communicate with GDB in two ways:
7906 A socket (TCP/IP) connection is typically started as follows:
7908 target remote localhost:3333
7910 This would cause GDB to connect to the gdbserver on the local pc using port 3333.
7912 It is also possible to use the GDB extended remote protocol as follows:
7914 target extended-remote localhost:3333
7917 A pipe connection is typically started as follows:
7919 target remote | openocd -c "gdb_port pipe; log_output openocd.log"
7921 This would cause GDB to run OpenOCD and communicate using pipes (stdin/stdout).
7922 Using this method has the advantage of GDB starting/stopping OpenOCD for the debug
7923 session. log_output sends the log output to a file to ensure that the pipe is
7924 not saturated when using higher debug level outputs.
7927 To list the available OpenOCD commands type @command{monitor help} on the
7930 @section Sample GDB session startup
7932 With the remote protocol, GDB sessions start a little differently
7933 than they do when you're debugging locally.
7934 Here's an examples showing how to start a debug session with a
7936 In this case the program was linked to be loaded into SRAM on a Cortex-M3.
7937 Most programs would be written into flash (address 0) and run from there.
7940 $ arm-none-eabi-gdb example.elf
7941 (gdb) target remote localhost:3333
7942 Remote debugging using localhost:3333
7944 (gdb) monitor reset halt
7947 Loading section .vectors, size 0x100 lma 0x20000000
7948 Loading section .text, size 0x5a0 lma 0x20000100
7949 Loading section .data, size 0x18 lma 0x200006a0
7950 Start address 0x2000061c, load size 1720
7951 Transfer rate: 22 KB/sec, 573 bytes/write.
7957 You could then interrupt the GDB session to make the program break,
7958 type @command{where} to show the stack, @command{list} to show the
7959 code around the program counter, @command{step} through code,
7960 set breakpoints or watchpoints, and so on.
7962 @section Configuring GDB for OpenOCD
7964 OpenOCD supports the gdb @option{qSupported} packet, this enables information
7965 to be sent by the GDB remote server (i.e. OpenOCD) to GDB. Typical information includes
7966 packet size and the device's memory map.
7967 You do not need to configure the packet size by hand,
7968 and the relevant parts of the memory map should be automatically
7969 set up when you declare (NOR) flash banks.
7971 However, there are other things which GDB can't currently query.
7972 You may need to set those up by hand.
7973 As OpenOCD starts up, you will often see a line reporting
7977 Info : lm3s.cpu: hardware has 6 breakpoints, 4 watchpoints
7980 You can pass that information to GDB with these commands:
7983 set remote hardware-breakpoint-limit 6
7984 set remote hardware-watchpoint-limit 4
7987 With that particular hardware (Cortex-M3) the hardware breakpoints
7988 only work for code running from flash memory. Most other ARM systems
7989 do not have such restrictions.
7991 Another example of useful GDB configuration came from a user who
7992 found that single stepping his Cortex-M3 didn't work well with IRQs
7993 and an RTOS until he told GDB to disable the IRQs while stepping:
7997 mon cortex_m maskisr on
7999 define hookpost-step
8000 mon cortex_m maskisr off
8004 Rather than typing such commands interactively, you may prefer to
8005 save them in a file and have GDB execute them as it starts, perhaps
8006 using a @file{.gdbinit} in your project directory or starting GDB
8007 using @command{gdb -x filename}.
8009 @section Programming using GDB
8010 @cindex Programming using GDB
8011 @anchor{programmingusinggdb}
8013 By default the target memory map is sent to GDB. This can be disabled by
8014 the following OpenOCD configuration option:
8016 gdb_memory_map disable
8018 For this to function correctly a valid flash configuration must also be set
8019 in OpenOCD. For faster performance you should also configure a valid
8022 Informing GDB of the memory map of the target will enable GDB to protect any
8023 flash areas of the target and use hardware breakpoints by default. This means
8024 that the OpenOCD option @command{gdb_breakpoint_override} is not required when
8025 using a memory map. @xref{gdbbreakpointoverride,,gdb_breakpoint_override}.
8027 To view the configured memory map in GDB, use the GDB command @option{info mem}
8028 All other unassigned addresses within GDB are treated as RAM.
8030 GDB 6.8 and higher set any memory area not in the memory map as inaccessible.
8031 This can be changed to the old behaviour by using the following GDB command
8033 set mem inaccessible-by-default off
8036 If @command{gdb_flash_program enable} is also used, GDB will be able to
8037 program any flash memory using the vFlash interface.
8039 GDB will look at the target memory map when a load command is given, if any
8040 areas to be programmed lie within the target flash area the vFlash packets
8043 If the target needs configuring before GDB programming, an event
8044 script can be executed:
8046 $_TARGETNAME configure -event EVENTNAME BODY
8049 To verify any flash programming the GDB command @option{compare-sections}
8051 @anchor{usingopenocdsmpwithgdb}
8052 @section Using OpenOCD SMP with GDB
8054 For SMP support following GDB serial protocol packet have been defined :
8056 @item j - smp status request
8057 @item J - smp set request
8060 OpenOCD implements :
8062 @item @option{jc} packet for reading core id displayed by
8063 GDB connection. Reply is @option{XXXXXXXX} (8 hex digits giving core id) or
8064 @option{E01} for target not smp.
8065 @item @option{JcXXXXXXXX} (8 hex digits) packet for setting core id displayed at next GDB continue
8066 (core id -1 is reserved for returning to normal resume mode). Reply @option{E01}
8067 for target not smp or @option{OK} on success.
8070 Handling of this packet within GDB can be done :
8072 @item by the creation of an internal variable (i.e @option{_core}) by mean
8073 of function allocate_computed_value allowing following GDB command.
8076 #Jc01 packet is sent
8078 #jc packet is sent and result is affected in $
8081 @item by the usage of GDB maintenance command as described in following example (2 cpus in SMP with
8082 core id 0 and 1 @pxref{definecputargetsworkinginsmp,,Define CPU targets working in SMP}).
8085 # toggle0 : force display of coreid 0
8091 # toggle1 : force display of coreid 1
8101 @node Tcl Scripting API
8102 @chapter Tcl Scripting API
8103 @cindex Tcl Scripting API
8107 The commands are stateless. E.g. the telnet command line has a concept
8108 of currently active target, the Tcl API proc's take this sort of state
8109 information as an argument to each proc.
8111 There are three main types of return values: single value, name value
8112 pair list and lists.
8114 Name value pair. The proc 'foo' below returns a name/value pair
8120 > set foo(you) Oyvind
8121 > set foo(mouse) Micky
8122 > set foo(duck) Donald
8130 me Duane you Oyvind mouse Micky duck Donald
8132 Thus, to get the names of the associative array is easy:
8134 foreach { name value } [set foo] {
8135 puts "Name: $name, Value: $value"
8139 Lists returned must be relatively small. Otherwise a range
8140 should be passed in to the proc in question.
8142 @section Internal low-level Commands
8144 By low-level, the intent is a human would not directly use these commands.
8146 Low-level commands are (should be) prefixed with "ocd_", e.g.
8147 @command{ocd_flash_banks}
8148 is the low level API upon which @command{flash banks} is implemented.
8151 @item @b{mem2array} <@var{varname}> <@var{width}> <@var{addr}> <@var{nelems}>
8153 Read memory and return as a Tcl array for script processing
8154 @item @b{array2mem} <@var{varname}> <@var{width}> <@var{addr}> <@var{nelems}>
8156 Convert a Tcl array to memory locations and write the values
8157 @item @b{ocd_flash_banks} <@var{driver}> <@var{base}> <@var{size}> <@var{chip_width}> <@var{bus_width}> <@var{target}> [@option{driver options} ...]
8159 Return information about the flash banks
8162 OpenOCD commands can consist of two words, e.g. "flash banks". The
8163 @file{startup.tcl} "unknown" proc will translate this into a Tcl proc
8164 called "flash_banks".
8166 @section OpenOCD specific Global Variables
8168 Real Tcl has ::tcl_platform(), and platform::identify, and many other
8169 variables. JimTCL, as implemented in OpenOCD creates $ocd_HOSTOS which
8170 holds one of the following values:
8173 @item @b{cygwin} Running under Cygwin
8174 @item @b{darwin} Darwin (Mac-OS) is the underlying operating sytem.
8175 @item @b{freebsd} Running under FreeBSD
8176 @item @b{linux} Linux is the underlying operating sytem
8177 @item @b{mingw32} Running under MingW32
8178 @item @b{winxx} Built using Microsoft Visual Studio
8179 @item @b{other} Unknown, none of the above.
8182 Note: 'winxx' was choosen because today (March-2009) no distinction is made between Win32 and Win64.
8185 We should add support for a variable like Tcl variable
8186 @code{tcl_platform(platform)}, it should be called
8187 @code{jim_platform} (because it
8188 is jim, not real tcl).
8196 @item @b{RTCK, also known as: Adaptive Clocking - What is it?}
8198 @cindex adaptive clocking
8201 In digital circuit design it is often refered to as ``clock
8202 synchronisation'' the JTAG interface uses one clock (TCK or TCLK)
8203 operating at some speed, your CPU target is operating at another.
8204 The two clocks are not synchronised, they are ``asynchronous''
8206 In order for the two to work together they must be synchronised
8207 well enough to work; JTAG can't go ten times faster than the CPU,
8208 for example. There are 2 basic options:
8211 Use a special "adaptive clocking" circuit to change the JTAG
8212 clock rate to match what the CPU currently supports.
8214 The JTAG clock must be fixed at some speed that's enough slower than
8215 the CPU clock that all TMS and TDI transitions can be detected.
8218 @b{Does this really matter?} For some chips and some situations, this
8219 is a non-issue, like a 500MHz ARM926 with a 5 MHz JTAG link;
8220 the CPU has no difficulty keeping up with JTAG.
8221 Startup sequences are often problematic though, as are other
8222 situations where the CPU clock rate changes (perhaps to save
8225 For example, Atmel AT91SAM chips start operation from reset with
8226 a 32kHz system clock. Boot firmware may activate the main oscillator
8227 and PLL before switching to a faster clock (perhaps that 500 MHz
8229 If you're using JTAG to debug that startup sequence, you must slow
8230 the JTAG clock to sometimes 1 to 4kHz. After startup completes,
8231 JTAG can use a faster clock.
8233 Consider also debugging a 500MHz ARM926 hand held battery powered
8234 device that enters a low power ``deep sleep'' mode, at 32kHz CPU
8235 clock, between keystrokes unless it has work to do. When would
8236 that 5 MHz JTAG clock be usable?
8238 @b{Solution #1 - A special circuit}
8240 In order to make use of this,
8241 your CPU, board, and JTAG adapter must all support the RTCK
8242 feature. Not all of them support this; keep reading!
8244 The RTCK ("Return TCK") signal in some ARM chips is used to help with
8245 this problem. ARM has a good description of the problem described at
8246 this link: @url{http://www.arm.com/support/faqdev/4170.html} [checked
8247 28/nov/2008]. Link title: ``How does the JTAG synchronisation logic
8248 work? / how does adaptive clocking work?''.
8250 The nice thing about adaptive clocking is that ``battery powered hand
8251 held device example'' - the adaptiveness works perfectly all the
8252 time. One can set a break point or halt the system in the deep power
8253 down code, slow step out until the system speeds up.
8255 Note that adaptive clocking may also need to work at the board level,
8256 when a board-level scan chain has multiple chips.
8257 Parallel clock voting schemes are good way to implement this,
8258 both within and between chips, and can easily be implemented
8260 It's not difficult to have logic fan a module's input TCK signal out
8261 to each TAP in the scan chain, and then wait until each TAP's RTCK comes
8262 back with the right polarity before changing the output RTCK signal.
8263 Texas Instruments makes some clock voting logic available
8264 for free (with no support) in VHDL form; see
8265 @url{http://tiexpressdsp.com/index.php/Adaptive_Clocking}
8267 @b{Solution #2 - Always works - but may be slower}
8269 Often this is a perfectly acceptable solution.
8271 In most simple terms: Often the JTAG clock must be 1/10 to 1/12 of
8272 the target clock speed. But what that ``magic division'' is varies
8273 depending on the chips on your board.
8274 @b{ARM rule of thumb} Most ARM based systems require an 6:1 division;
8275 ARM11 cores use an 8:1 division.
8276 @b{Xilinx rule of thumb} is 1/12 the clock speed.
8278 Note: most full speed FT2232 based JTAG adapters are limited to a
8279 maximum of 6MHz. The ones using USB high speed chips (FT2232H)
8280 often support faster clock rates (and adaptive clocking).
8282 You can still debug the 'low power' situations - you just need to
8283 either use a fixed and very slow JTAG clock rate ... or else
8284 manually adjust the clock speed at every step. (Adjusting is painful
8285 and tedious, and is not always practical.)
8287 It is however easy to ``code your way around it'' - i.e.: Cheat a little,
8288 have a special debug mode in your application that does a ``high power
8289 sleep''. If you are careful - 98% of your problems can be debugged
8292 Note that on ARM you may need to avoid using the @emph{wait for interrupt}
8293 operation in your idle loops even if you don't otherwise change the CPU
8295 That operation gates the CPU clock, and thus the JTAG clock; which
8296 prevents JTAG access. One consequence is not being able to @command{halt}
8297 cores which are executing that @emph{wait for interrupt} operation.
8299 To set the JTAG frequency use the command:
8307 @item @b{Win32 Pathnames} Why don't backslashes work in Windows paths?
8309 OpenOCD uses Tcl and a backslash is an escape char. Use @{ and @}
8310 around Windows filenames.
8323 @item @b{Missing: cygwin1.dll} OpenOCD complains about a missing cygwin1.dll.
8325 Make sure you have Cygwin installed, or at least a version of OpenOCD that
8326 claims to come with all the necessary DLLs. When using Cygwin, try launching
8327 OpenOCD from the Cygwin shell.
8329 @item @b{Breakpoint Issue} I'm trying to set a breakpoint using GDB (or a frontend like Insight or
8330 Eclipse), but OpenOCD complains that "Info: arm7_9_common.c:213
8331 arm7_9_add_breakpoint(): sw breakpoint requested, but software breakpoints not enabled".
8333 GDB issues software breakpoints when a normal breakpoint is requested, or to implement
8334 source-line single-stepping. On ARMv4T systems, like ARM7TDMI, ARM720T or ARM920T,
8335 software breakpoints consume one of the two available hardware breakpoints.
8337 @item @b{LPC2000 Flash} When erasing or writing LPC2000 on-chip flash, the operation fails at random.
8339 Make sure the core frequency specified in the @option{flash lpc2000} line matches the
8340 clock at the time you're programming the flash. If you've specified the crystal's
8341 frequency, make sure the PLL is disabled. If you've specified the full core speed
8342 (e.g. 60MHz), make sure the PLL is enabled.
8344 @item @b{Amontec Chameleon} When debugging using an Amontec Chameleon in its JTAG Accelerator configuration,
8345 I keep getting "Error: amt_jtagaccel.c:184 amt_wait_scan_busy(): amt_jtagaccel timed
8346 out while waiting for end of scan, rtck was disabled".
8348 Make sure your PC's parallel port operates in EPP mode. You might have to try several
8349 settings in your PC BIOS (ECP, EPP, and different versions of those).
8351 @item @b{Data Aborts} When debugging with OpenOCD and GDB (plain GDB, Insight, or Eclipse),
8352 I get lots of "Error: arm7_9_common.c:1771 arm7_9_read_memory():
8353 memory read caused data abort".
8355 The errors are non-fatal, and are the result of GDB trying to trace stack frames
8356 beyond the last valid frame. It might be possible to prevent this by setting up
8357 a proper "initial" stack frame, if you happen to know what exactly has to
8358 be done, feel free to add this here.
8360 @b{Simple:} In your startup code - push 8 registers of zeros onto the
8361 stack before calling main(). What GDB is doing is ``climbing'' the run
8362 time stack by reading various values on the stack using the standard
8363 call frame for the target. GDB keeps going - until one of 2 things
8364 happen @b{#1} an invalid frame is found, or @b{#2} some huge number of
8365 stackframes have been processed. By pushing zeros on the stack, GDB
8368 @b{Debugging Interrupt Service Routines} - In your ISR before you call
8369 your C code, do the same - artifically push some zeros onto the stack,
8370 remember to pop them off when the ISR is done.
8372 @b{Also note:} If you have a multi-threaded operating system, they
8373 often do not @b{in the intrest of saving memory} waste these few
8377 @item @b{JTAG Reset Config} I get the following message in the OpenOCD console (or log file):
8378 "Warning: arm7_9_common.c:679 arm7_9_assert_reset(): srst resets test logic, too".
8380 This warning doesn't indicate any serious problem, as long as you don't want to
8381 debug your core right out of reset. Your .cfg file specified @option{jtag_reset
8382 trst_and_srst srst_pulls_trst} to tell OpenOCD that either your board,
8383 your debugger or your target uC (e.g. LPC2000) can't assert the two reset signals
8384 independently. With this setup, it's not possible to halt the core right out of
8385 reset, everything else should work fine.
8387 @item @b{USB Power} When using OpenOCD in conjunction with Amontec JTAGkey and the Yagarto
8388 toolchain (Eclipse, arm-elf-gcc, arm-elf-gdb), the debugging seems to be
8389 unstable. When single-stepping over large blocks of code, GDB and OpenOCD
8390 quit with an error message. Is there a stability issue with OpenOCD?
8392 No, this is not a stability issue concerning OpenOCD. Most users have solved
8393 this issue by simply using a self-powered USB hub, which they connect their
8394 Amontec JTAGkey to. Apparently, some computers do not provide a USB power
8395 supply stable enough for the Amontec JTAGkey to be operated.
8397 @b{Laptops running on battery have this problem too...}
8399 @item @b{USB Power} When using the Amontec JTAGkey, sometimes OpenOCD crashes with the
8400 following error messages: "Error: ft2232.c:201 ft2232_read(): FT_Read returned:
8401 4" and "Error: ft2232.c:365 ft2232_send_and_recv(): couldn't read from FT2232".
8402 What does that mean and what might be the reason for this?
8404 First of all, the reason might be the USB power supply. Try using a self-powered
8405 hub instead of a direct connection to your computer. Secondly, the error code 4
8406 corresponds to an FT_IO_ERROR, which means that the driver for the FTDI USB
8407 chip ran into some sort of error - this points us to a USB problem.
8409 @item @b{GDB Disconnects} When using the Amontec JTAGkey, sometimes OpenOCD crashes with the following
8410 error message: "Error: gdb_server.c:101 gdb_get_char(): read: 10054".
8411 What does that mean and what might be the reason for this?
8413 Error code 10054 corresponds to WSAECONNRESET, which means that the debugger (GDB)
8414 has closed the connection to OpenOCD. This might be a GDB issue.
8416 @item @b{LPC2000 Flash} In the configuration file in the section where flash device configurations
8417 are described, there is a parameter for specifying the clock frequency
8418 for LPC2000 internal flash devices (e.g. @option{flash bank $_FLASHNAME lpc2000
8419 0x0 0x40000 0 0 $_TARGETNAME lpc2000_v1 14746 calc_checksum}), which must be
8420 specified in kilohertz. However, I do have a quartz crystal of a
8421 frequency that contains fractions of kilohertz (e.g. 14,745,600 Hz,
8422 i.e. 14,745.600 kHz). Is it possible to specify real numbers for the
8425 No. The clock frequency specified here must be given as an integral number.
8426 However, this clock frequency is used by the In-Application-Programming (IAP)
8427 routines of the LPC2000 family only, which seems to be very tolerant concerning
8428 the given clock frequency, so a slight difference between the specified clock
8429 frequency and the actual clock frequency will not cause any trouble.
8431 @item @b{Command Order} Do I have to keep a specific order for the commands in the configuration file?
8433 Well, yes and no. Commands can be given in arbitrary order, yet the
8434 devices listed for the JTAG scan chain must be given in the right
8435 order (jtag newdevice), with the device closest to the TDO-Pin being
8436 listed first. In general, whenever objects of the same type exist
8437 which require an index number, then these objects must be given in the
8438 right order (jtag newtap, targets and flash banks - a target
8439 references a jtag newtap and a flash bank references a target).
8441 You can use the ``scan_chain'' command to verify and display the tap order.
8443 Also, some commands can't execute until after @command{init} has been
8444 processed. Such commands include @command{nand probe} and everything
8445 else that needs to write to controller registers, perhaps for setting
8446 up DRAM and loading it with code.
8448 @anchor{faqtaporder}
8449 @item @b{JTAG TAP Order} Do I have to declare the TAPS in some
8452 Yes; whenever you have more than one, you must declare them in
8453 the same order used by the hardware.
8455 Many newer devices have multiple JTAG TAPs. For example: ST
8456 Microsystems STM32 chips have two TAPs, a ``boundary scan TAP'' and
8457 ``Cortex-M3'' TAP. Example: The STM32 reference manual, Document ID:
8458 RM0008, Section 26.5, Figure 259, page 651/681, the ``TDI'' pin is
8459 connected to the boundary scan TAP, which then connects to the
8460 Cortex-M3 TAP, which then connects to the TDO pin.
8462 Thus, the proper order for the STM32 chip is: (1) The Cortex-M3, then
8463 (2) The boundary scan TAP. If your board includes an additional JTAG
8464 chip in the scan chain (for example a Xilinx CPLD or FPGA) you could
8465 place it before or after the STM32 chip in the chain. For example:
8468 @item OpenOCD_TDI(output) -> STM32 TDI Pin (BS Input)
8469 @item STM32 BS TDO (output) -> STM32 Cortex-M3 TDI (input)
8470 @item STM32 Cortex-M3 TDO (output) -> SM32 TDO Pin
8471 @item STM32 TDO Pin (output) -> Xilinx TDI Pin (input)
8472 @item Xilinx TDO Pin -> OpenOCD TDO (input)
8475 The ``jtag device'' commands would thus be in the order shown below. Note:
8478 @item jtag newtap Xilinx tap -irlen ...
8479 @item jtag newtap stm32 cpu -irlen ...
8480 @item jtag newtap stm32 bs -irlen ...
8481 @item # Create the debug target and say where it is
8482 @item target create stm32.cpu -chain-position stm32.cpu ...
8486 @item @b{SYSCOMP} Sometimes my debugging session terminates with an error. When I look into the
8487 log file, I can see these error messages: Error: arm7_9_common.c:561
8488 arm7_9_execute_sys_speed(): timeout waiting for SYSCOMP
8494 @node Tcl Crash Course
8495 @chapter Tcl Crash Course
8498 Not everyone knows Tcl - this is not intended to be a replacement for
8499 learning Tcl, the intent of this chapter is to give you some idea of
8500 how the Tcl scripts work.
8502 This chapter is written with two audiences in mind. (1) OpenOCD users
8503 who need to understand a bit more of how Jim-Tcl works so they can do
8504 something useful, and (2) those that want to add a new command to
8507 @section Tcl Rule #1
8508 There is a famous joke, it goes like this:
8510 @item Rule #1: The wife is always correct
8511 @item Rule #2: If you think otherwise, See Rule #1
8514 The Tcl equal is this:
8517 @item Rule #1: Everything is a string
8518 @item Rule #2: If you think otherwise, See Rule #1
8521 As in the famous joke, the consequences of Rule #1 are profound. Once
8522 you understand Rule #1, you will understand Tcl.
8524 @section Tcl Rule #1b
8525 There is a second pair of rules.
8527 @item Rule #1: Control flow does not exist. Only commands
8528 @* For example: the classic FOR loop or IF statement is not a control
8529 flow item, they are commands, there is no such thing as control flow
8531 @item Rule #2: If you think otherwise, See Rule #1
8532 @* Actually what happens is this: There are commands that by
8533 convention, act like control flow key words in other languages. One of
8534 those commands is the word ``for'', another command is ``if''.
8537 @section Per Rule #1 - All Results are strings
8538 Every Tcl command results in a string. The word ``result'' is used
8539 deliberatly. No result is just an empty string. Remember: @i{Rule #1 -
8540 Everything is a string}
8542 @section Tcl Quoting Operators
8543 In life of a Tcl script, there are two important periods of time, the
8544 difference is subtle.
8547 @item Evaluation Time
8550 The two key items here are how ``quoted things'' work in Tcl. Tcl has
8551 three primary quoting constructs, the [square-brackets] the
8552 @{curly-braces@} and ``double-quotes''
8554 By now you should know $VARIABLES always start with a $DOLLAR
8555 sign. BTW: To set a variable, you actually use the command ``set'', as
8556 in ``set VARNAME VALUE'' much like the ancient BASIC langauge ``let x
8557 = 1'' statement, but without the equal sign.
8560 @item @b{[square-brackets]}
8561 @* @b{[square-brackets]} are command substitutions. It operates much
8562 like Unix Shell `back-ticks`. The result of a [square-bracket]
8563 operation is exactly 1 string. @i{Remember Rule #1 - Everything is a
8564 string}. These two statements are roughly identical:
8568 echo "The Date is: $X"
8571 puts "The Date is: $X"
8573 @item @b{``double-quoted-things''}
8574 @* @b{``double-quoted-things''} are just simply quoted
8575 text. $VARIABLES and [square-brackets] are expanded in place - the
8576 result however is exactly 1 string. @i{Remember Rule #1 - Everything
8580 puts "It is now \"[date]\", $x is in 1 hour"
8582 @item @b{@{Curly-Braces@}}
8583 @*@b{@{Curly-Braces@}} are magic: $VARIABLES and [square-brackets] are
8584 parsed, but are NOT expanded or executed. @{Curly-Braces@} are like
8585 'single-quote' operators in BASH shell scripts, with the added
8586 feature: @{curly-braces@} can be nested, single quotes can not. @{@{@{this is
8587 nested 3 times@}@}@} NOTE: [date] is a bad example;
8588 at this writing, Jim/OpenOCD does not have a date command.
8591 @section Consequences of Rule 1/2/3/4
8593 The consequences of Rule 1 are profound.
8595 @subsection Tokenisation & Execution.
8597 Of course, whitespace, blank lines and #comment lines are handled in
8600 As a script is parsed, each (multi) line in the script file is
8601 tokenised and according to the quoting rules. After tokenisation, that
8602 line is immedatly executed.
8604 Multi line statements end with one or more ``still-open''
8605 @{curly-braces@} which - eventually - closes a few lines later.
8607 @subsection Command Execution
8609 Remember earlier: There are no ``control flow''
8610 statements in Tcl. Instead there are COMMANDS that simply act like
8611 control flow operators.
8613 Commands are executed like this:
8616 @item Parse the next line into (argc) and (argv[]).
8617 @item Look up (argv[0]) in a table and call its function.
8618 @item Repeat until End Of File.
8621 It sort of works like this:
8624 ReadAndParse( &argc, &argv );
8626 cmdPtr = LookupCommand( argv[0] );
8628 (*cmdPtr->Execute)( argc, argv );
8632 When the command ``proc'' is parsed (which creates a procedure
8633 function) it gets 3 parameters on the command line. @b{1} the name of
8634 the proc (function), @b{2} the list of parameters, and @b{3} the body
8635 of the function. Not the choice of words: LIST and BODY. The PROC
8636 command stores these items in a table somewhere so it can be found by
8639 @subsection The FOR command
8641 The most interesting command to look at is the FOR command. In Tcl,
8642 the FOR command is normally implemented in C. Remember, FOR is a
8643 command just like any other command.
8645 When the ascii text containing the FOR command is parsed, the parser
8646 produces 5 parameter strings, @i{(If in doubt: Refer to Rule #1)} they
8650 @item The ascii text 'for'
8651 @item The start text
8652 @item The test expression
8657 Sort of reminds you of ``main( int argc, char **argv )'' does it not?
8658 Remember @i{Rule #1 - Everything is a string.} The key point is this:
8659 Often many of those parameters are in @{curly-braces@} - thus the
8660 variables inside are not expanded or replaced until later.
8662 Remember that every Tcl command looks like the classic ``main( argc,
8663 argv )'' function in C. In JimTCL - they actually look like this:
8667 MyCommand( Jim_Interp *interp,
8669 Jim_Obj * const *argvs );
8672 Real Tcl is nearly identical. Although the newer versions have
8673 introduced a byte-code parser and intepreter, but at the core, it
8674 still operates in the same basic way.
8676 @subsection FOR command implementation
8678 To understand Tcl it is perhaps most helpful to see the FOR
8679 command. Remember, it is a COMMAND not a control flow structure.
8681 In Tcl there are two underlying C helper functions.
8683 Remember Rule #1 - You are a string.
8685 The @b{first} helper parses and executes commands found in an ascii
8686 string. Commands can be seperated by semicolons, or newlines. While
8687 parsing, variables are expanded via the quoting rules.
8689 The @b{second} helper evaluates an ascii string as a numerical
8690 expression and returns a value.
8692 Here is an example of how the @b{FOR} command could be
8693 implemented. The pseudo code below does not show error handling.
8695 void Execute_AsciiString( void *interp, const char *string );
8697 int Evaluate_AsciiExpression( void *interp, const char *string );
8700 MyForCommand( void *interp,
8705 SetResult( interp, "WRONG number of parameters");
8709 // argv[0] = the ascii string just like C
8711 // Execute the start statement.
8712 Execute_AsciiString( interp, argv[1] );
8716 i = Evaluate_AsciiExpression(interp, argv[2]);
8721 Execute_AsciiString( interp, argv[3] );
8723 // Execute the LOOP part
8724 Execute_AsciiString( interp, argv[4] );
8728 SetResult( interp, "" );
8733 Every other command IF, WHILE, FORMAT, PUTS, EXPR, everything works
8734 in the same basic way.
8736 @section OpenOCD Tcl Usage
8738 @subsection source and find commands
8739 @b{Where:} In many configuration files
8740 @* Example: @b{ source [find FILENAME] }
8741 @*Remember the parsing rules
8743 @item The @command{find} command is in square brackets,
8744 and is executed with the parameter FILENAME. It should find and return
8745 the full path to a file with that name; it uses an internal search path.
8746 The RESULT is a string, which is substituted into the command line in
8747 place of the bracketed @command{find} command.
8748 (Don't try to use a FILENAME which includes the "#" character.
8749 That character begins Tcl comments.)
8750 @item The @command{source} command is executed with the resulting filename;
8751 it reads a file and executes as a script.
8753 @subsection format command
8754 @b{Where:} Generally occurs in numerous places.
8755 @* Tcl has no command like @b{printf()}, instead it has @b{format}, which is really more like
8761 puts [format "The answer: %d" [expr $x * $y]]
8764 @item The SET command creates 2 variables, X and Y.
8765 @item The double [nested] EXPR command performs math
8766 @* The EXPR command produces numerical result as a string.
8768 @item The format command is executed, producing a single string
8769 @* Refer to Rule #1.
8770 @item The PUTS command outputs the text.
8772 @subsection Body or Inlined Text
8773 @b{Where:} Various TARGET scripts.
8776 proc someproc @{@} @{
8777 ... multiple lines of stuff ...
8779 $_TARGETNAME configure -event FOO someproc
8780 #2 Good - no variables
8781 $_TARGETNAME confgure -event foo "this ; that;"
8782 #3 Good Curly Braces
8783 $_TARGETNAME configure -event FOO @{
8786 #4 DANGER DANGER DANGER
8787 $_TARGETNAME configure -event foo "puts \"Time: [date]\""
8790 @item The $_TARGETNAME is an OpenOCD variable convention.
8791 @*@b{$_TARGETNAME} represents the last target created, the value changes
8792 each time a new target is created. Remember the parsing rules. When
8793 the ascii text is parsed, the @b{$_TARGETNAME} becomes a simple string,
8794 the name of the target which happens to be a TARGET (object)
8796 @item The 2nd parameter to the @option{-event} parameter is a TCBODY
8797 @*There are 4 examples:
8799 @item The TCLBODY is a simple string that happens to be a proc name
8800 @item The TCLBODY is several simple commands seperated by semicolons
8801 @item The TCLBODY is a multi-line @{curly-brace@} quoted string
8802 @item The TCLBODY is a string with variables that get expanded.
8805 In the end, when the target event FOO occurs the TCLBODY is
8806 evaluated. Method @b{#1} and @b{#2} are functionally identical. For
8807 Method @b{#3} and @b{#4} it is more interesting. What is the TCLBODY?
8809 Remember the parsing rules. In case #3, @{curly-braces@} mean the
8810 $VARS and [square-brackets] are expanded later, when the EVENT occurs,
8811 and the text is evaluated. In case #4, they are replaced before the
8812 ``Target Object Command'' is executed. This occurs at the same time
8813 $_TARGETNAME is replaced. In case #4 the date will never
8814 change. @{BTW: [date] is a bad example; at this writing,
8815 Jim/OpenOCD does not have a date command@}
8817 @subsection Global Variables
8818 @b{Where:} You might discover this when writing your own procs @* In
8819 simple terms: Inside a PROC, if you need to access a global variable
8820 you must say so. See also ``upvar''. Example:
8822 proc myproc @{ @} @{
8823 set y 0 #Local variable Y
8824 global x #Global variable X
8825 puts [format "X=%d, Y=%d" $x $y]
8828 @section Other Tcl Hacks
8829 @b{Dynamic variable creation}
8831 # Dynamically create a bunch of variables.
8832 for @{ set x 0 @} @{ $x < 32 @} @{ set x [expr $x + 1]@} @{
8834 set vn [format "BIT%d" $x]
8838 set $vn [expr (1 << $x)]
8841 @b{Dynamic proc/command creation}
8843 # One "X" function - 5 uart functions.
8844 foreach who @{A B C D E@}
8845 proc [format "show_uart%c" $who] @{ @} "show_UARTx $who"
8851 @node OpenOCD Concept Index
8852 @comment DO NOT use the plain word ``Index'', reason: CYGWIN filename
8853 @comment case issue with ``Index.html'' and ``index.html''
8854 @comment Occurs when creating ``--html --no-split'' output
8855 @comment This fix is based on: http://sourceware.org/ml/binutils/2006-05/msg00215.html
8856 @unnumbered OpenOCD Concept Index
8860 @node Command and Driver Index
8861 @unnumbered Command and Driver Index