[time-nuts] Serial port splitter s/w

David J Taylor david-taylor at blueyonder.co.uk
Thu Feb 27 01:42:44 EST 2014


From: Chris Albertson

You might want to think a little more about which to get.  The Pi is OK and
will work fine but look at "BeagleBone Black".  It's a little nicer for
hardware hackers. Cost is $5 different.   You can read specs and the
respective forums.

One thing to watch out for is that all ARM boards run on 3.3 volts.  The
serial ports are 3.3 volts.  Don't connect a 5 volt signal and certainly
NOT a real RS232 level signal
===================================

It would be interesting to see a performance comparison between the RPi and 
the BBB. when running NTP from a PPS signal.  The RPi is much more popular 
and has a much wider user base, though.

I've used mine for a 1.09 GHz ADS-B receiver (aircraft tracking), logging 
room temperature, as a wall-clock synced from NTP, of course, and for 
various other applications.  The GPS units you can get these days support 
3.3V operation so that's not a difficulty in practice.  I've used these 
units for both "with soldering" and "no soldering needed" choices:

With soldering:
  http://www.adafruit.com/products/746

"No soldering required"
  http://ava.upuaut.net/store/index.php?route=product/product&path=59_60&product_id=95

Certainly, for external true RS-232 devices an interface is needed, but 
these can again be bought for the Raspberry Pi (data only):
  http://www.davidhunt.ie/?p=3091
  http://www.abelectronics.co.uk/products/3/Raspberry-Pi/29/Serial-Pi-RS232-Interface

Cheers,
David
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 




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