[time-nuts] Trimble GPS board

Angus not.again at btinternet.com
Sun Aug 23 09:56:40 EDT 2015

>On the left front corner of the board is the 1 PPS connector.
>To the right of that connector are 4 unpopulated holes for a
>connector. I traced those out and found 2 went to a RS-232
>chip that appears to be a different type depending on which of
>the boards you receive. The left hole is ground (RS-232 pin 5
>on the computer end), then the next hole is not connected, then
>RS-232 pin 2, then pin 3 being the hole with the square index pad
>on the right. Using a terminal emulator program and 57600 8N1N
>I was able to communicate with the board. Typing '?' will give
>you a long list of all the commands it will accept. For instance,
>'STAT' and 'POSSTAT' are 2 of the commands that will give you
>info on how the board is working. Typing *IDN? at the UCCM-P >
>prompt returns 57964-60 for my board and POSSTAT shows up to 12
>satellites can be tracked. The date code on my unit is 2009.
>The board seems to work well but the OCXO runs pretty hot so it
>probably isn't a double oven. The multicontact connector probably
>has most of the functions and LED signals available but I couldn't
>see using it so I'll get whatever signals I want directly off the
>pc board.

Hi Arthur,

That's interesting - I connected my one up to Trimble studio and
others, but got no joy - I never thought of just asking it :)

I went through the connections on the other pins, but most are just to
the FPGA or 0V. Most don't appear to be doing a lot - maybe they need
whatever is meant to be connected to this board to be connected before
they do anything.

There is another serial port which is the same baud rate but appears
to be binary, and prattles away every 2 seconds:
Pin 36 goes to Pin 4 of the UART (RX)
Pin 37 goes to Pin 8 of the UART (TX)

Pin 2 has binary data of about 64 bits at 1.6us/bit - looks like maybe
a timer or similar.

(Above pin numbers assume V+ is connected to pins 44-50 and are
hopefully correct, but always worth checking)


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