Preliminary Cosmic Chasm hardware info

I sat down this morning and dumped my CC eprom sets, and started
looking at the hardware. Nice, simple vector design (as opposed
to Aztarac!). It looks like it has 8 commands which appear in
the top 3 bits of a 16 bit word. The low 12 bits are the operand.
It appears to have a vector PC that starts at 0 in the shared
static RAM (20k total). Since there is only a 12 bit PC, I assume
it only can address RAM :-) (..just looked on the RAM schematic,
and there are only 16 lines on the "ram address bus" (oops, the
vector PC is 16 bits wide, the top bits are always loaded with 0
on a jump..).

The instruction set:

0 Halt
1 Jump <12 bit adr>
2 Color <rrrrggggbbbb>
3 delta Y
4 Y
5 delta X
6 X
7 vector length

It appears that there are three interrupts (6840 timer, vg, audio)
and a watchdog that can be disabled.
Received on Wed Nov 19 10:49:40 1997