[time-nuts] Ball/Efratom MFS-209 Rubidium GPSDO...

Chuck Harris cfharris at erols.com
Sat Dec 13 14:27:21 EST 2014

And as I feared, the MGPS display is telling the truth, there
is something wrong with the GPS module's ability to check the
feed line for shorts and opens, and something wrong with the
motherboard's ADC module.

At least the communication between the MGPS and the GPS engine
is working properly...

-Chuck Harris

Chuck Harris wrote:
> After chatting with John Miles, and Paul (ziggy), I was reminded
> that TTL RS232 is not a good thing around a pedantic protocol
> analyzer.
> 4V signal swings would work with the analyzer's strict +/-3V
> thresholds, except for that wonderful excuse for a UART that
> Trimble used, putting a big glitch dead center in each sent
> bit position.
> The protocol analyzer saw that glitch drop below 3V, and
> just knew it was a start bit.  And, that coupled with using
> 9600,8,N,1 instead of Trimble's favorite 9600,8,O,1 settings
> made for the interesting data smearing I was seeing.
> Now, I am getting properly formed TSIP packets.
> Time to decode them and see what they mean.
> More later,
> -Chuck Harris

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