20 Oct
2004
20 Oct
'04
1:38 p.m.
On Wed, Oct 20, 2004 at 07:46:27PM -0400, Dave Dunfield wrote:
Correct. It's got separate transmit and receive (parallel) data pins,
baud rate clock inputs, word lenght/parity/stop bit configuration pins,
and so on. It's quite easy to connect to random logic.
Hi Ethan,
It's got a regulator, and some logic - a 6402 UART, and another
completely unmarked 40-pin chip - I'm guessing it's an PET-IEEE
controller of some sort.
OK... the 6402 UART is one of the ones that I think can be interfaced
to simple logic - i.e., it doesn't _require_ a microprocessor to read or write to it. I think there's one in an
IEEE-serial box I have from
TNW. I know there's no uP in there.
There was a relatively common PET->RS232 interface in the UK called the
B200. It contained a 6402-like UART, a baud rate generator ckip, a couple
of 2708s (one as a PETSCII<->ASCII converter and address decoder, the
other as the handshake state machine logic) and not a lot else. I
hesitate to called it an IEEE488-> RS232 interface, since the handshake
timing was way off, and while it works with PETs, it fails to work with
many other IEEE488 controllers.
As for the 40-pin chip, unless it's something like a 6500/1 (a micro-
controller-like relative of the 6502, as found in the 1520 plotter),
Unless there's some EPROM/ROM in there, it's unlikely to be a
microprocessor. It might even be a gate array.
Other apparent
power sources from the connector head off into a maze
of op-amps and other analog circuitry, even with schematics it would
take a bit of work to figure out what supplies it was designed for...
Hmm... that makes it hard.