[GreenKeys] RS232 to TTY Loop Boards

[Lester Veenstra]

So, does anyone want to (or hopefully, all ready done)  the code for this
platform to get from USB ASCII  to TTL  level Baudot (and ASCII) at the
usual baud rates?


Lester B Veenstra  MØYCM K1YCM W8YCM
lester at veenstras.com

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-----Original Message-----
From: Bob Camp [mailto:kb8tq at n1k.org] 
Sent: Monday, February 16, 2015 12:50 PM
To: lester at veenstras.com
Subject: Re: [GreenKeys] RS232 to TTY Loop Boards

Hi

Indeed, the whole baud rate / stop bit format thing is a can of worms. The
more picky you get
the more worms you have to deal with. 

Something like this:

http://www.mouser.com/ProductDetail/Freescale-Semiconductor/FRDM-KL43Z/?qs=s
GAEpiMZZMtzpSA5GSDwa4h%2fTfDsQpc4eHEHoEETWww%3d

for $15 (why that one - I have on in my hand ..) has USB on it already as
well as a pair of MCU’s. It’s got enough 
horsepower to bit bang anything you would ever want to play with on a
current loop device.  You can either bit bang
the stuff or run it in and out of the SPI port. 

That’s the easy part, maybe a weekend project. Write it in C, run in in MQX.
Do it all with free tools. Open source the whole thing.

The higher level problem is the PC side of running the beast. You hit it
with ASCII and run it in ASCII. The 
Freedom board takes care of all the ASCII to 5, 6, 7 level code(s). There
needs to be a Windows / Mac / Linux / Free BSD / Solaris / Dos 3.1 / 
.
program on the 
other end to switch things around. Also whatever terminal program you are
running needs to understand what is on the other end. 

Again just code, probably a bit more than a weekend project. Think a bit
about the list of OS’s before you start writing
..

Toss in the usual “cool stuff” and both sides get a bit more complex. 

Still not much of a board. Not very expensive to do. Just some code to write
and debug.

Bob