More on Arduino

[wb4jfi at knology.net]

-----Original Message----- 
From: Robert E. Seastrom
Sent: Monday, April 16, 2012 11:35 AM
To: wb4jfi at knology.net
Cc: andre.kesteloot at ieee.org ; Tacos
Subject: Re: More on Arduino


<wb4jfi at knology.net> writes:

> The average amateur will never write C code for ANY
> processor/development board.  To him or her, it's all about being able
> to implement what someone else has done.  If you want to build a
> device that receives Kenwood/Elecraft CAT commands and parse them out
> to three different ham rigs or equipment (using isolated RS232 ports),
> you cannot easily do that on an Uno.  But, you CAN do that on an
> Arduino Mega 2560.

If I were retired I might take a comment like that as a challenge.

Standard baud rate for CAT/CI-V is 1200, no?  That should be well
within the capabilities of
http://arduino.cc/hu/Tutorial/SoftwareSerial

Why not a CAT/CI-V to i2c to CAT program that allows target ID
rewriting and an Arduino per radio (or maybe two radios per target
Arduino if you want to get fancy and the SoftwareSerial library
doesn't need a horrendous rewrite to pull it off)?

-r

CAT is not necessarily limited to CI-V speeds.  The Elecraft K3 CAT speed is 
completely adjustable, but defaults to 38,400 (a LOT faster than 1200).  So, 
buy the Mega and have four hardware UARTs, no bit-banging required. 
Bit-banging is not a free lunch.  I'm sure the software UART code is 
properly debugged, but it is still another point of failure.  Get three or 
four of them going at once, and watch out.  And it steals processor cycles. 
If you have them to spare, no problem.  If you are close to running out of 
them, watch out.

Another point:  The Uno only has ONE UART serial port.  And that is shared 
with the USB communications as well.  So, you cannot use that one serial 
port for USB communications with a host, CAT commands out to the rigs, AND 
debugging, all at the same time.  Hello bit-banger.  Or, pay twice as much 
for either an Arduino Mega or a ChipKIT Max32.

Keep in mind that we started by talking about the "average amateur".  You 
Rob, and most of tacos are "extra-special amateurs" by definition!

I'm not too thrilled about sending I2C commands across wires between boards 
in a potentially high RF environment.  I2C was designed to communicated 
between processors on the same board, or within a single device.  Running 
I2C signals as wire antennas behind your linear is probably not a good idea. 
Plus, the cost of one Arduino Mega is roughly the same as two Unos, so why 
use multiple boards and serial antenna lines where a single Mega or ChipKIT 
will do?  Adding the I2C stuff and inter-Uno communications is way more 
complicated than just buying the more sophisticated board.

Most important:
If you are doing stuff with Arduinos, or other things, WRITE IT UP FOR THE 
NEWSLETTER!

Terry