Re: Help IDing unknown cards...

[et472@FreeNet.Carleton.CA (Michael Black)]

Jules (julesrichardsonuk@yahoo.co.uk) writes:
> 
> Z80 Card:  Actually a "Z80 Card II" made by Creative. Presumably
> software exists for one of these somewhere still. No on-board memory,
> and 4 unknown DIP-switches in the lower-right corner. CPU is Z80-A,
> card seems to have been made in late 1982.
> 
But what's different about it that makes you think it's different
from the average Microsoft CP/M card?

> 
> 80-column card:  Marked as 'Chinex' and made by Creative, presumably
> necessary software for this still exists somewhere? Any ideas what the
> 'middle' connector (with no cable attached) is for?

I'm not looking at the pictures, but 80-column cards were usually
made with the 6845 controller.  From memory, I thought there was a pin
for a light pen input.  Depending on how many pins that connector has,
perhaps it's for this.  Or, again depending on pin count, perhaps it's
for the Apple's regular video signal, so whichever source you are using,
it will feed the monitor?  I'm sure it was common to do this with those
boards.

> 
> ZIF-socketed card ("unknown_04.jpg" on the website):  The ZIF socket
> is a 28-pin unit. I'd say it was a programmer, but wouldn't it need an
> external 24V (??) supply if that were true? The 40-pin chip is marked
> as "S6821P", whatever one of those is. The first 3 of the switches are
> labelled as '16', the next 3 as '32' and the last 4 (overlapping by 1
> with the previous 3) as '64'.
> 
The 6821 is a "PIA" (Parallel Interface Adaptor), with two sets of
8bits of I/O.  You can program each of the ports for input or output,
or a combination of both.  There is an address for each port, and
a control register on an adjacent address.

> Card with 8 LEDs and 4 empty 16-pin DIL sockets ("unknown_02.jpg" on
> the website): Any ideas? Possibly a joystick controller or something
> and the joysticks plugged in via the DIL sockets? The two 40-pin chips
> are 6522's. There's a back of 8 DIP-switches on board, plus a switch
> in the top-right which just seems to enable or disable the LEDs as far
> as I can see.
> 
6522s are like the 6521s, in that they are parallel I/O ports.  But
in addition to the two parallel I/Os, there is a shift register inside,
and and a timer and some additional control pins.

  Michael