Unknown Apple 2 cards

From: Davison, Lee <Lee.Davison_at_merlincommunications.com>
Date: Thu Jun 5 07:12:00 2003

Hello Jules,

> 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?

Looks like the Vpp generator is on the far right below the multiturn
pot. It will be something like TL497.

> The 40-pin chip is marked as "S6821P", whatever one of those is.

68xx series paralell I/O chip.

> 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'.

First three on for 2716, next 3 on for 2732 and the last 4 on for 2764.

> Card with 8 LEDs and 4 empty 16-pin DIL sockets ("unknown_02.jpg" on the
> website): Any ideas?

Looks like a digital I/O card. The 6522s are also paralell I/O chips.
Leads to the outside world would plug into the DIL sockets.

Cheers,
        Lee.


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Received on Thu Jun 05 2003 - 07:12:00 BST

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