[GreenKeys] Parallel to Current Loop Conversion - 6402 UART circuits

[Chris Elmquist]

On Thursday (12/04/2014 at 01:22PM -0800), Doug via GreenKeys wrote:
> Cory.  Not sure if this is what you are looking for, but the old 6402 UART IC works fine.  The first link below shows it in a parallel to serial
> converter mode.  I have used this exact circuit with optical tape punch reader equipment, and it works fine.  You may have to configure some of 
> the control pins different for your setup.  In my setup, I used the signal from the sprocket hole as the trigger input, pin 23.  I was using it at 110 
> and 300 baud.  I ran the serial output into a cheap $2 USB serial adapter from eBay, and it worked fine on my Windows XP computer using 
> hyperterminal to send and receive data.  I don't think they still make the 6402 , but you can still find it pretty easily.  A modern UART might be 
> cheaper, and will have more functions, but I wanted to keep it old school in my project.  If anyone is curious, the second link is for the 6402 in a 
> serial to parallel mode. 

Indeed, a classic UART is what you want.  6402, 1602, AY-5-1013, were all
the rage in their day.  These do not need any microprocessor to configure
them-- it's done by pulling pins high or low and they have seperate 8-bit
ports for both the transmit and the receive data.  All can be configured
for 5, 6, 7, or 8 data bits on the serial side and I'm pretty sure they
will all do 1.5 stop bits when in 5-bit mode too.

Unicorn Electronics still carry them as NOS,

http://www.unicornelectronics.com/IC/UART.html

Chris
-- 
Chris Elmquist