Fun with CC40s

[JGardner]

I've been poking around in ROM, trying to learn a bit more about

Hook tables in System RAM. A few years ago Acadiel asked me to

write a pgm to dump the CC40 system ROMs - I'd thought the 4-8K

ROM pages @>D000-E000 were accessible in DEBUG with the "R"

command, but this turns out to be only partially true; you can only

see Page 3 in DEBUG with the "D" or "M" commands - So I wrote a

short asm routine that uses the ROM paging bits @ P25.0 & P25.1 to

read the 4 ROM pages consecutively into cartridge RAM, where they

are directly accessible from BASIC. This turns out to be useful for

disassembling ROM with DEBUG, so I thought I'd post the routine I'm

using now - It moves the page you're interested in from >D000-E000

to >5000-6FFF in cartridge RAM; you can put it anywhere you want,

but 4K boundaries are convenient, as >D000 = >5000, & so on... And

sInce the code's in RAM you can set breakpoints & run it, after adjusting

hard-coded addresses...

Not a world-beater, but very short (39 bytes) which means you can enter

the code by hand, through DEBUG - No PCIF necessary.

Jack

 

[JGardner]

Bugfix - Change >201A in attachment from >7F to >FF.

Attachment has also been corrected - I hope...

 

[curtis]

Would it be possible to send the output to a printer, such as the printer 80.

I'm looking at dumping the tiger stripe ROM and don't have a RAM cartridge for it.

 

[JGardner]

Sure, if you know the protocol the printer expects.

But it might be simpler to write the data to file on a PC, through a Serial-to-USB

Converter to a Terminal Emulator on the PC. Do you have a RS232/USB converter?

IIRC I bit-banged 9600 8N1 on the TI-74, to Tera Term on the PC end - Worked ok.

Should'nt be a big deal to re-write for CC40.

 

[JGardner]

What I used between the '74 & the PC: https://www.adafruit.com/product/284

Genuine FTDI, works great.

 

[JGardner]

OK, I found the Printer 80 user manual at whtech, and dumping ROM to it

looks doable - I've never seen, or used, a Printer 80...

 

[curtis]

Really? They're actually a fairly nifty piece of kit. If you don't have thermal paper you can use the one-shot ribbon that provides pretty good printout. Sadly, the ribbons are getting hard to find, but normal roll fax paper works pretty good. Just have to rig up a roller dispenser.

OK,
I've never seen, or used, a Printer 80...

 

[JGardner]

In my sheltered life, I'd never heard of a Printer 80 - Sounds good though.