Mystery IC: Allen Bradley 314B102
cisin at xenosoft.com
Mon Dec 14 18:21:53 CST 2015
On Tue, 15 Dec 2015, Mike Ross wrote:
> Maybe, but Selectrics aren't exactly fast devices; there's a whole lot
> of potential 'no, wait, I'm not ready!' conditions. Would they all be
> ORed onto one pin?
possibly. It's been done that way before.
> That was my conclusion too. The old Western I/O ads I've seen
> definitely refer to it as having an 'ASCII' or 'parallel' interface.
> Assuming they only ever made the two models; I suppose it *could* be
> some variant of RS232, with very non-standard pinouts - but the ads
> are specific; they made a smart terminal with 6800 CPU & serial
> interface, and a dumb printer with an 'ASCII parallel' interface. And
> that's all I have to go on, beyond prodding the hardware.
REMEMBER, "ASCII parallel" does NOT necessarily mean "centronics-style",
as was used on TRS80, IBM PC, etc. "Centronics-style" was a good system,
but it was NOT the only one.
"ASCII parallel" could just as easily mean SEVEN bit, with a bit or two in
each direction for handshaking. "ASCII" was SEVEN bits, not EIGHT.
> That would be well weird. Still trying to work out what exactly it was
> intended to hook up to; a standard parallel port with a special cable,
There was a time, 35 years ago, when "standard parallel" was an oxymoron.
> leads, 7 lines... I'd expect to see 8 data lines all going to the same
> place if it was anything resembling standard Centronics but with a
> weird pinout. So I'm scratching my head still over just exactly what
> it was supposed to hook up to.
something other than "Centronics"?
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