I know it's bad form to reply to your own posts, but here it is.
--- Ethan Dicks <ethan_dicks_at_yahoo.com> wrote:
>
> Today I finally picked up an RCA Studio II home video game...
> ...it uses the RCA 1802 processor (and the 1861 video chip).
>
> Does anyone out there have any pointers to internals information?
I just opened it up... some previous owner has scrawled lots of notes in pencil
about what does what. Address lines labelled, component symbols (on the
solder side), memory address ranges, controller key numbers... Lots of good
info.
The board itself resembles the Quest Elf in its layout style - lots of
room and waves of curved, parallel traces. Outside of the RF cage are
the CDP1802CE, an RCA TA10171V1 (the video chip), four 1822 256x4 SRAMs
($0800 - $09FF), four 1831 ROMs (512 bytes each) [$0000 - $07FF] and the
glue logic: one 4042, one 4001 and one 4515 (which I think is the latch
for the game controllers). The timing and power section is a 555 and a
7805, pretty pedestrian stuff. The date codes suggest a timeframe of 1Q77.
The ROM carts use a .154"-spacing single-sided 22-pin connector, so RatShack
has boards I can use to make my own.
It's just stunning to open this up and have this kind of documentation in
place. The 1802 is a simple beast. This guy obviously did what I was going
to do - start with the known CPU signals and work out. What I _wasn't_
planning on doing was marking up the original. I'm glad he did.
One odd thing about this design - DC power come into the RF switchbox
that clamps to the TV. There is a single RCA cable that connects the
switchbox and the game unit. It appears as if power goes one way down the
cable and video data goes the other way. Strange.
-ethan
=====
Infinet has been sold. The domain is going away in February.
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Received on Fri Dec 24 1999 - 15:49:26 GMT