Joachim Thiemann wrote:
How difficult would it be to copy a ROM? The bank
ROMs are simply
EPROMs with sticky paper labels, I think I could simply erase one and
the reprogram it with a homebuild adapter so as not to damage the
carrier...
The EPROMs are most likely Motorola MCM68764, or (slightly less desirable)
MCM68766. It should be no problem to erase and reprogram them.
The only interesting (IMHO) ROMs you can program into an MC68764
(limited to 8K bytes) are the Microsoft BASIC ROM and the Scientific
Calculator ROM. SnapBASIC and SnapFORTH require 16KB, and there are
no 16KB EPROMs that will fit the 24-pin carrier.
Is there any information out there on how to program
the HHC in 6502
assembly? memory maps, keyboard and LCD interface, etc...
I've been starting to reverse-engineer it, but it's a lot of work.
Someone that did some HHC reverse-engineering back in 1981-1982 (due
to inadequate documentation from Friends Amis) is sending me his
notes, and I should have them in a few days. However, he advises me
that since they were just notes to himself, they are probably too
cryptic to be very useful. Still, I'm hoping I can tease some
information out of them.
Eric