12 Jul
2012
12 Jul
'12
10:31 a.m.
On Wed, Jul 11, 2012 at 4:02 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Yep.
Check the connector traces for RS232 pins 15 and 17 - if those are
routed through from the 26-pin connector to a line receiver, it's
entirely possible that this would be a sync serial port (or optionally
async/sync depending on setting). There are a couple other sync
serial arrangements, but the one that's common (for sync) and
supported, involves the board receiving clocking from the
modem/modem-eliminator.
IIRC the Z8530 is a dual-channel device. I wonder if one channel is just
not used, or if 2 serial ports end up on that 26 pi nehader (which would
then not be wried to go straight to a DB25). I think the OP is going to
have to start tracing connections :-)
Also, we're all assuming it goes in a computer. It might be from some
kind of RS232 switch, statitical multiplexer, network interface, or
something like that.
Main chip
is an AMD Z8530PC. There's a PAL and a MC1488 & 9,
otherwise the rest is 74LS TTL. All socketed. 26 pin internal header.
No external sockets. Date codes are mostly 1987.
It certainly feels like some sort of RS232 serial card, based on the
Well, the Z85030 is a fancy serial chip that does synchronous as well as
asynchronous. As for what it's for, the obvious classic use
fo the Z8530 is the Mac, so
maybe Appletalk. But the buffers are wrong for that. Maybe to talk to an
X25 network or soemthing?
Perhaps. Ordinary Apple serial cards used 6551 ACIA UARTs. Those are a lot easier to talk to than the Z8530, so one would
expect there
The 6551 (and 6850) are easier to interfce to the 6502 bus and easier to
write software drivers for than the Z8530. The latter chip would not have
been used unless there's a good reason for it.
would be a reason to use a Z8530 that's fancier
than just needing to
push bytes to a dumb device.
We agree :-)
-tony