Apple II hardware design

From: A.R. Duell <ard12_at_eng.cam.ac.uk>
Date: Mon Jun 23 09:37:30 1997

[Apple ]['s again]

> Hmm? What was that bit-banged serial port?

A little Apple card (Async Serial Interface or something) that contained a
PROM (P8 or P8A), and a few TTL chips that formed a single-bit I/O port.
There were RS232 and current loop buffers on the card. Probably about 10
chips total.

I have one, and the manual which gives schematics and PROM source.

> There was an unspectacular serial card for the ][. I don't recall it
> being a bit banger, just that the combination of it and the printer I
> was using at the time (an IDS BrighterWriter) wasn't smart enough to
> manage any sort of common flow control, so that I had to run it at 300

The card I am thinking of supported no handshakes at all (well, it tied
RTS to CTS and DTR to DSR and CD). XON/XOFF was sort-of supported if you
went slowly enough. And for some inexplicable reason the card was wired as
a _modem_ (out on 3, in on 2), not a terminal.

> baud. I thought it had some sort of UART-like thing, but maybe my
> brain is going again.
>
> Hmm, I think it was called the Asynchronous Serial Interface or

That may be the same card. I tried to use one for a period to talk to a
laboratory instrument. It nearly drove me mad.

> something like that. There was also a Synchronous Serial Interface
> that (I recently found out) was the Silentype printer interface.

The Silentype card was a custom interface AFAIK. There was a synchronous
serial part to that card, but it was nothing like any other synchronous
interface.

> -Frank McConnell


--
-tony
ard12_at_eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Received on Mon Jun 23 1997 - 09:37:30 BST

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