KayPro II keyboard schematic

Ethan Dicks ethan.dicks at usap.gov
Thu Dec 20 13:39:07 CST 2007

On Thu, Dec 20, 2007 at 10:56:09AM -0800, Chuck Guzis wrote:
> > From: "Andrew Lynch" <lynchaj at yahoo.com>
> > Does anyone have a schematic for *simple* hardware only circuit using a
> > commonly available UART, like an 8251 or 8250, to do the serial to
> > parallel conversion?  I am looking for a schematic which I can easily
> > modify to strap the UART to 300bps operation.
> If you don't want programmable logic, an 8251 or 8250 isn't going to 
> be what you want.  Try a TR1602 or TR1865 or any of the other 
> "hardwire" UARTS--set parity, data bits, etc. by connecting 
> appropriate pins to Vcc or GND; put the serial data in on one pin and 
> take the parallel data out on 8 pins.  No programming needed.

The RCA CDP1854 or the Intersil (and others) IM6402 are great for this,
and shouldn't be difficult to find.


Ethan Dicks, A-333-S     Current South Pole Weather at 20-Dec-2007 at 19:30 Z
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Ethan.Dicks at usap.gov            http://penguincentral.com/penguincentral.html

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