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Jakub Husak
2020-05-16 00:25:17 +02:00
parent 53965989b8
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README.md
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This software is for use with my super simple flash cartridge (no gals, only 3 74xx elements and some caps and resistors). Top side is that without elements. This software is for use with my super simple flash cartridge (no gals, only 3 74xx elements and some caps and resistors). Top side is that without elements.
The cartridge is driven by addresses D500-D580; write to D500 sets the first bank - this is boot bank. Write to D501 sets second bank etc. The max usable number with cart on is set by write to D51F; write to D580 switches off the cartridge. The cartridge is driven by addresses D500-D580; write to D500 sets the first bank - this is default boot bank. Write to D501 sets second bank etc. The max usable number with cart on is set by write to D51F; write to D580 switches off the cartridge.
The internal construction of JatariCart allows utilise max 256kB of flash memory (32 banks) The internal construction of JatariCart allows utilise max 256kB of flash memory (32 banks) or of course PROM/EPROM memory.
The memory package is plcc32.
Remember to fool the Operating System not to hang up by cart on/off, by: Flash memory can be programmed/flashed from Atari platform by flasher application, wchich you can find in "flashwriteexample" catalog.
The flasher must be (for now) preassembled using mads assembler with proper rom file included bank by bank (the flasher source does it by itself).
If you want to write your own cartridge access, remember to fool the Operating System not to hang up by cart on/off, by:
<pre> <pre>
carton (x - bank to switch) carton (x - bank to switch)
pha pha
sei sei
sta $D580,x sta $D500,x
sta wsync ; needed for ntsc, no big difference in speed sta wsync ; needed for ntsc, no big difference in speed
sta wsync ; needed for ntsc sta wsync ; needed for ntsc
lda trig3 lda trig3
@@ -22,12 +26,15 @@ carton (x - bank to switch)
rts rts
</pre> </pre>
after each access. This will let the system think as cartridge never was switched/removed/inserted. Of course it is better (much better, obligue) that there is no display list, video memory and no interrupts in the area a000-bfff, which can be anything when bank swapping.
Files and descriptions:
flashwritelib.asx - 6502 code library for formatting flash/formatting sector and write byte. flashwritelib.asx - 6502 code library for formatting flash/formatting sector and write byte.
flashsrite.asx - 6502 code for generate flasher (when compiled, it contains either flash routines and cartridge image itself) flashsrite.asx - 6502 code for generate flasher (when compiled, it contains either flash routines and cartridge image itself)
crc16_v2.asm - crc16 library for fast checking every sector (when flash is damaged, it happens that write sector damages another) crc16_v2.asm - crc16 library for fast checking every sector (when flash is damaged, sometimes it happens that write sector damages another)
Compile (mads needed, http://mads.atari8.info): Compile (mads needed, http://mads.atari8.info):