Access to peripheral parts of UmTRX.

Andrey Sviyazov andreysviyaz at gmail.com
Fri Jan 20 18:54:01 UTC 2012


Today I used a cheap external active GPS antenna with a thin 5 m cable (see
attached DS), but I had to solder SMA connector instead of unknown to me.
The current consumption of the antenna 11мА @ 3V.
About 2 minutes after a cold start, the status LED starts blinking 0.5 Hz
and 1PPS signal appears at the Clock output connector.
So, now we can to start work with the self-tuning of the TCXO.

Anyway, how realistic in the near time to implement an simple command
translator through the FTDI - FPGA for the SPI to each LMS to get at least
the signals of their synthesizers (also to UART for GPS, to SPI for DAC of
TCXO and etc. :).
It can be a simple protocol with virtual control registers addressing and
read/write or a few separate firmwares for each goal.
With such a tool at any time we will be able to check UmTRX operation with
some simple signals and an spectrum analyzer.
Also it will be very helpful for the understanding of how to work with LMS
control registers, which is poorly described in the documentation.
Have any thoughts or suggestions on this?

Best regards,
Andrey Sviyazov.
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