1 <!doctype linuxdoc system>
5 <title>Atari Lynx specific information for cc65
6 <author>Karri Kaksonen, <htmlurl url="mailto:karri@sipo.fi" name="karri@sipo.fi">
7 Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
11 An overview over the Atari Lynx runtime system as it is implemented for the
15 <!-- Table of contents -->
18 <!-- Begin the document -->
22 This file contains an overview of the Atari Lynx runtime system as it comes
23 with the cc65 C compiler. It describes the memory layout, Lynx specific header
24 files, available drivers, and any pitfalls specific to that platform.
26 Please note that Lynx specific functions are just mentioned here, they are
27 described in detail in the separate <htmlurl url="funcref.html" name="function
28 reference">. Even functions marked as "platform dependent" may be available on
29 more than one platform. Please see the function reference for more
33 <sect>Binary format<p>
35 The standard binary output format generated by the linker for the Lynx target
36 is a machine language program with an executable header. It is of course
37 possible to change this behaviour by using a modified startup file and linker
40 You can also produce real carts with directory structures and encrypted
41 headers by modifying the startup and linker config files. There is a simple
42 example archive called <tt/lynx-cart-demo/ in the <htmlurl
43 url="ftp://ftp.musoftware.de/pub/uz/cc65/contrib/" name="contrib directory">
44 that shows how to create a complete bootable Lynx cart.
46 <sect>Memory layout<p>
48 cc65 generated programs with the default setup run with the I/O area and the
49 kernal enabled, which gives a usable memory range of $400 - $BE3F.
50 All boot ROM entry points may be called directly without additional code.
56 No conio support is currently available for the Lynx.
59 The Lynx "flabode" keys, Opt 1, Pause and Opt 2 are implemented using the
60 conio interface. The only characters the keyboard is able to produce are
61 'R' for Restart (Opt 1 + Pause), 'F' for flip (Opt 2 + Pause),
62 'P' for pause, '1' for Opt 1, '2' for Opt 2, '3' for Opt 1 + Opt 2 and
63 '?' for all keys down at the same time.
66 The C runtime stack is located at $BE3F and growing downwards.
69 The C heap is located at the end of the program and grows towards the C
76 <sect>Platform specific header files<p>
78 Programs containing Lynx specific code may use the <tt/lynx.h/ header file.
81 <sect1>Lynx specific functions<p>
84 <item>lynx_change_framerate
85 <item>lynx_eeprom_erase
86 <item>lynx_eeprom_read
87 <item>lynx_eeprom_write
92 <sect1>Hardware access<p>
94 The following pseudo variables declared in the <tt/lynx.h/ header file do
95 allow access to hardware located in the address space. Some variables are
96 structures, accessing the struct fields will access the chip registers.
100 <tag><tt/MIKEY/</tag>
101 The <tt/MIKEY/ structure allows access to MIKEY chip. See the <tt/_mikey.h/
102 header file located in the include directory for the declaration of the
106 The <tt/SUZY/ structure allows access to SUZY chip. See the <tt/_suzy.h/
107 header file located in the include directory for the declaration of the
114 <sect>Loadable drivers<p>
116 <sect1>Graphics drivers<p>
118 A TGI driver for the standard graphics mode (160×102 in 16 colors) is
119 available, but must be statically linked, because no file I/O is available.
120 See the documentation for the <htmlurl url="co65.html" name="co65 utility">
121 for information on how to do that.
123 The TGI driver is implemented as a dual buffering device. To use it as a
124 single-buffer device set draw page and view page to the same value 0 or 1;
126 The TGI driver has a few Lynx-specific extensions.
128 Calling tgi_sprite(spr) or tgi_ioctl(0, spr) will display a standard Lynx
131 Calling tgi_flip() or tgi_ioctl(1, 0) will do a flip screen.
133 Calling tgi_setbgcolor(bgcolor) or tgi_ioctl(2, bgindex) will set the text
134 background color to the index defined by bgindex. If bgindex is 0 then the
135 background color is transparent.
137 To set the framerate of the display hardware call tgi_setframerate(rate) or
138 tgi_ioctl(3, rate). The supported framerates are 50, 60 and 75 frames per
139 second. Actually there is no real reason to use anything else than 75 frames
142 To check if the drawing engine is busy with the previous swap you can
143 call tgi_busy or tgi_ioctl(4, 0). It returns 0 if idle and 1 if busy
145 To update displays you can call tgi_updatedisplay() or tgi_ioctl(4, 1) it
146 will wait for the next VBL interrupt and set the draw buffer to the
147 view buffer. The draw buffer is also changed to (drawbuffer xor 1).
149 Set an address for a subroutine you want to call at every VBL by calling
150 tgi_setvblhook(addr) or tgi_ioctl(5, addr).
152 <sect1>Extended memory drivers<p>
154 No extended memory drivers are currently available for the Lynx.
157 <sect1>Joystick drivers<p>
159 A joystick driver for the standard buttons is available, but must be
160 statically linked, because no file I/O is available. See the documentation for
161 the <htmlurl url="co65.html" name="co65 utility"> for information on how to do
164 The joystick will check to see if the screen is flipped or not in the install
165 routine and adapt itself to the currect state.
167 <sect1>Mouse drivers<p>
169 No mouse drivers are currently available for the Lynx.
172 <sect1>RS232 device drivers<p>
174 No serial drivers are currently available for the Lynx.
184 At this point in time there is no support for the cart filesystem yet. I have
185 a <tt/lynx-cart-demo/ example project that uses an interrupt driven display,
186 has support for the cart filesystem and an abcmusic sound module.
188 At some point in time we may find a way to rewrite these to fit the way the
189 cc65 drivers require. But for the time being you can create less portable
190 applications using these Lynx specific modules in <tt/lynx-cart-demo/.
193 <sect>Bugs/Feedback<p>
195 If you have problems using the library, if you find any bugs, or if you're
196 doing something interesting with it, I would be glad to hear from you. Feel
197 free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
198 name="uz@cc65.org">).
204 This software is provided 'as-is', without any expressed or implied
205 warranty. In no event will the authors be held liable for any damages
206 arising from the use of this software.
208 Permission is granted to anyone to use this software for any purpose,
209 including commercial applications, and to alter it and redistribute it
210 freely, subject to the following restrictions:
213 <item> The origin of this software must not be misrepresented; you must not
214 claim that you wrote the original software. If you use this software
215 in a product, an acknowledgment in the product documentation would be
216 appreciated but is not required.
217 <item> Altered source versions must be plainly marked as such, and must not
218 be misrepresented as being the original software.
219 <item> This notice may not be removed or altered from any source