CC-40 - Technical thread

[+acadiel]

Just to keep some of this info from disappearing in the ether.

 

The CC-40 has two roms:  a 32K ROM (banked in 8K at a time from >D000->EFFF), and a processor ROM (2K, at the top end of the address space, >F800->FFFF).  The DEBUG program has a facility to bank switch, but it doesn't work (probably because the original designers didn't want people bank switching and dumping the ROM!  LOL)

 

To dump the ROM, put a 32K RAM cartridge in the cartridge slot in the CC-40, and you can actually dump the cartridge using this assembly (input using DEBUG).  It copies each bank 8K at a time into the 32K RAM cartridge address space from >5000->CFFF.  You can then crawl the 32K RAM address space and spit out the ROM via RS232.  This is how I dumped the CC-40 ROM for use with the MAME emulation.  This will be useful for anyone who has a CC-40+ to dump it's rom, which is different from the -40.

 

The 2K Processor ROM can be dumped directly from BASIC.  Note that the CC-40+ has a 4K Processor ROM (TMS70C40) because it includes cassette routines in the processor ROM (>F000->FFFF - note that >F000->F7FF is unused in the CC-40.)

 

This works on a TI-74, with the appropriate addresses,
but I don't have a working CC40 32K cartridge to test it
with on a CC40. Let me know what happens... 

Jack

52 03 88 CF FF 5B 88 EF FF 59 A3 FC 19 94 19
9A 59 9B 5B DB 59 DB 5B 7D FF 59 E6 F3 7D CF
58 E6 EE C2 5D FF E6 E0 F4

Load address: >2000; Execution Address: >2000

Result:
ROM Pg. 3 copied to >B000 - >CFFF
ROM Pg. 2 copied to >9000 - >AFFF
ROM Pg. 1 copied to >7000 - >8FFF
ROM Pg. 0 copied to >5000 - >6FFF

 

Converting cartridges to binary: