1 <!doctype linuxdoc system>
5 <title>Atari Lynx specific information for cc65
7 <url url="mailto:karri@sipo.fi" name="Karri Kaksonen">,<newline>
8 <url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">
12 An overview over the Atari Lynx runtime system as it is implemented for the
16 <!-- Table of contents -->
19 <!-- Begin the document -->
23 This file contains an overview of the Atari Lynx runtime system as it comes
24 with the cc65 C compiler. It describes the memory layout, Lynx specific header
25 files, available drivers, and any pitfalls specific to that platform.
27 Please note that Lynx specific functions are just mentioned here, they are
28 described in detail in the separate <url url="funcref.html" name="function
29 reference">. Even functions marked as "platform dependent" may be available on
30 more than one platform. Please see the function reference for more
34 <sect>Building your first Hello World application<p>
36 Here is a small traditional Hello World program for the Atari Lynx.
44 tgi_install(tgi_static_stddrv);
50 tgi_setcolor(COLOR_GREEN);
51 tgi_outtextxy(0, 0, "Hello World");
58 The lynx.h contains all kind of system dependent things.
60 The tgi.h contains the graphics driver functions.
62 The 6502.h is needed for executing the CLI() command.
64 As the Atari Lynx does not have ASCII characters available you need to use
65 the Tiny Graphics Interface library for producing letters on the screen.
67 The cc65 compiler suite has a graphics library called "Tiny Graphics
68 Interface". This interface has some relocatable code. In order to use this
69 in your own program you need to load it at run time.
71 Unfortunately the Lynx does not have a disk drive from where to load it.
72 Therefore you must already load it at compile time. The easiest way is to
73 automatically link it in statically from the Lynx C library.
76 cl65 -t lynx -o game.lnx main.c
79 This will create a bootable cart image called game.lnx
82 <sect>Binary format<p>
84 The standard binary output format generated by the linker for the Lynx target
85 is a cart image. By specifying the config file lynx-bll.cfg the linker will
86 generate BLL download compatible binary files.
88 It is of course possible to change this behaviour by using a modified startup
89 file and linker config.
91 The bootloader used in the cc65 lynx library uses a very minimal bootloader
92 that does not check the cart or show a title screen.
94 The advantage of this bootloader is that it allows creation of cart images to
99 Block size Rom size Description
100 512 bytes 128k Standard old games like Warbirds
101 1024 bytes 256k Most common format for homebrew. Also newer games like Lemmings
102 2048 bytes 512k Largest games like EOTB
105 <sect>Memory layout<p>
107 cc65 generated programs with the default setup run with the I/O area and the
108 kernal enabled, which gives a usable memory range of $200 - $C037.
112 0000 - 00FF Zero page
113 0100 - 01FF Machine stack
115 A058 - C037 Collision buffer
116 C038 - E017 Screen buffer 1
117 E018 - FFF7 Screen buffer 0
118 FFF8 - FFFF Hardware vectors
123 No conio support is currently available for the Lynx.
126 The Lynx "flabode" keys, Opt 1, Pause and Opt 2 are implemented using the
127 conio interface. The only characters the keyboard is able to produce are
128 'R' for Restart (Opt 1 + Pause), 'F' for flip (Opt 2 + Pause),
129 'P' for pause, '1' for Opt 1, '2' for Opt 2, '3' for Opt 1 + Opt 2 and
130 '?' for all keys down at the same time.
133 The C runtime stack is located at $C037 (or $A057 if collision
134 detection is enabled) and growing downwards.
137 The C heap is located at the end of the program and grows towards the C
141 The collision detection screen is at $A058 if it is enabled. The
142 double buffered screens are at $C038 and $E018.
148 <sect>Platform specific header files<p>
150 Programs containing Lynx specific code may use the <tt/lynx.h/ header file.
153 <sect1>Lynx specific functions<p>
156 <item>lynx_eeprom_erase
157 <item>lynx_eeprom_read
158 <item>lynx_eeprom_write
167 <sect1>Hardware access<p>
169 The following pseudo variables declared in the <tt/lynx.h/ header file do
170 allow access to hardware located in the address space. Some variables are
171 structures, accessing the struct fields will access the chip registers.
175 <tag><tt/MIKEY/</tag>
176 The <tt/MIKEY/ structure allows access to MIKEY chip. See the <tt/_mikey.h/
177 header file located in the include directory for the declaration of the
181 The <tt/SUZY/ structure allows access to SUZY chip. See the <tt/_suzy.h/
182 header file located in the include directory for the declaration of the
189 <sect>Loadable drivers<p>
191 The names in the parentheses denote the symbols to be used for static linking of the drivers.
194 <sect1>Graphics drivers<p>
198 <tag><tt/lynx-160-102-16.tgi (lynx_160_102_16_tgi)/</tag>
199 A TGI driver for the standard graphics mode (160×102 in 16 colors).
201 The TGI driver is implemented as an interrupt driven dual buffering device.
202 To use it as a single-buffer device set draw page and view page to the same
205 The TGI driver has a few Lynx-specific extensions.
207 Calling tgi_sprite(spr) or tgi_ioctl(0, spr) will display a standard Lynx
210 Calling tgi_flip() or tgi_ioctl(1, 0) will do a flip screen.
212 Calling tgi_setbgcolor(bgcolor) or tgi_ioctl(2, bgindex) will set the text
213 background color to the index defined by bgindex. If bgindex is 0 then the
214 background color is transparent.
216 To set the framerate of the display hardware call tgi_setframerate(rate) or
217 tgi_ioctl(3, rate). The supported framerates are 50, 60 and 75 frames per
218 second. Actually there is no real reason to use anything else than 75 frames
221 To check if the drawing engine is busy with the previous swap you can
222 call tgi_busy or tgi_ioctl(4, 0). It returns 0 if idle and 1 if busy
224 To update displays you can call tgi_updatedisplay() or tgi_ioctl(4, 1) it
225 will wait for the next VBL interrupt and set the draw buffer to the
226 view buffer. The draw buffer is also changed to (drawbuffer xor 1).
228 You can also enable or disable collision detection by a call to
229 tgi_setcollisiondetection(active) or tgi_ioctl(5, active). The collision
230 result is located before the sprite structure by default in this driver.
232 In order to reserve memory for the collision detection buffer you need to
233 specify lynx-coll.cfg as the configuration file to the linker.
238 <sect1>Extended memory drivers<p>
240 No extended memory drivers are currently available for the Lynx.
243 <sect1>Joystick drivers<p>
247 <tag><tt/lynx-stdjoy.joy (lynx_stdjoy_joy)/</tag>
248 A joystick driver for the standard buttons.
253 <sect1>Mouse drivers<p>
255 No mouse drivers are currently available for the Lynx.
258 <sect1>RS232 device drivers<p>
262 <tag><tt/lynx-comlynx.ser (lynx_comlynx_ser)/</tag>
263 A serial driver for the ComLynx port.
265 The ComLynx port has Tx and Rx wired together. Every byte is sent
266 to all connected Lynxes. Only one Lynx can send at a time. There is no
267 protocol created for communication. You are on your own.
269 If the Lynx returns framing error then it is likely that another Lynx is
270 sending data at the same time.
272 The Lynx can also send a break and receive a break. The Lynx break is
273 recognized if the bit is down for 24 bit cycles or more.
275 To send a break you just set the break bit. The length of the break depends
276 on how long this bit is down.
278 The driver supports the baudrates:
296 The parity bit supports MARK and SPACE. It also supports EVEN and ODD parity
297 but the parity bit is included in the calculation. Most of us don't want it
298 this way. But there is nothing we can do about it.
300 The Lynx hardware will always check parity on incoming traffic. Currently
301 the driver cannot receive data from standard PC's due to this parity bug.
302 For working with Lynx to Lynx communication use EVEN parity.
304 To send data to standard PC's use MARK or SPACE as parity setting.
306 There is always only one stop bit. And the data length is always 8 bits.
308 We have no handshaking available. Even software handshake is impossible
309 as ComLynx has only one wire for the data.
311 Both transmit and receive are interrupt driven.
322 At this point in time there is no support for the cart filesystem yet. I have
323 a <tt/lynx-cart-demo/ example project that uses an interrupt driven display,
324 has support for the cart filesystem and an abcmusic sound module.
326 At some point in time we may find a way to rewrite these to fit the way the
327 cc65 drivers require. But for the time being you can create less portable
328 applications using these Lynx specific modules in <tt/lynx-cart-demo/.
333 This software is provided 'as-is', without any expressed or implied
334 warranty. In no event will the authors be held liable for any damages
335 arising from the use of this software.
337 Permission is granted to anyone to use this software for any purpose,
338 including commercial applications, and to alter it and redistribute it
339 freely, subject to the following restrictions:
342 <item> The origin of this software must not be misrepresented; you must not
343 claim that you wrote the original software. If you use this software
344 in a product, an acknowledgment in the product documentation would be
345 appreciated but is not required.
346 <item> Altered source versions must be plainly marked as such, and must not
347 be misrepresented as being the original software.
348 <item> This notice may not be removed or altered from any source