[net.games.video] coleco

ronnie (01/05/83)

I have a feeling that part of the reason that Coleco made it so easy
to download and copy their cartridges is that it also makes it very
easy to produce new cartridges and they wouldn't mind if a few
random people started making cartridges thus increasing the popularity
of the machine. I would be interested in finding out the instruction
set for their CPU including memory addresses for I/O, etc.

				-Ron

tretheweyj (01/11/83)

   My boss at the OSU Computer Center recently bought a ColecoVision, and
out of curiosity, looked inside.  There was a Z-80 in there.  Of course,
there are many readily available sources of instruction set documentation.
I/O is performed using ports (PIO, PPI, USART, whatever) or other appropriate
TTL.  It may be possible to tell where I/O "goes to/comes from" just by
looking at the board and the chip numbers (buy a TTL handbook).  If that
is not possible, you may have to resort to pulling PROM's out of sockets,
reading them elsewhere and disassembling the machine code.  I am sure you
will violate any warranty by doing this.
   (If I have made any blatant errors, flames to:)

                  Jim Trethewey, Oregon State University, Corvallis.