23 Jun
1997
23 Jun
'97
2:37 a.m.
[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(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill