[Coco] CoCo 3 patch question

[Roger Taylor]

Does anyone know if the CoCo patches the Disk ROM if it's available?

The reason I ask is that I'm developing an embedded system EPROM 
which poses as Disk BASIC by having the "DK" bytes at the top.  From 
M.E.S.S., a CoCo 1 or 2 boots into my ROM fine and shows a title 
screen, but from the CoCo 3 modes, my title text has about 5 or 6 
bytes of garbage in it, which tells me something is changing part of 
the area where my text is stored within the ROM.

I tried starting my ROM with:
   fcc "DK"
   jmp Start
   fzb 256  (CCASM's way of filling with 256 0's)
Start nop

And this works in the emulator, but I'm not sure what OTHER bytes are 
altered by the CoCo 3 patch routines.  This leads me to ask yet 
another question... how does the CoCo 3 (if it's patching Disk BASIC) 
deal with the other DOS brands?

Anyway, I've created a nice ROM which turns a CoCo into an embedded 
server.  It boots up hands-free-ready to accept MP3 cassette files or 
those sent by cocotape.exe from a PC, or a real tape deck, etc.  As 
soon as the file is over, it executes.  This allows the control 
program to be uploaded just by sending the audio stream into the CoCo 
once. If you hit RESET it runs the control program again (or last 
program uploaded) instead of resetting the CoCo back to a hard 
start.  The control program can be a game or any other single-record 
ML tape file.  I've been sending games to the remote CoCo for my kid 
to play and all he's doing is toggling the power button when he wants 
a new one sent.  The game starts up automatically.  Talk about 
nice.  The serious side to this project is that no keyboard or 
monitor is required if the plans are to do an emedded project.  Just 
send power to the CoCo board and run a cassette cable to an MP3 
player, select (I'll call it control.mp3) and walk away.  Or connect 
a laptop speaker, type cocotape control.bin, and walk away.

-- 
Roger Taylor

http://www.wordofthedayonline.com