Hackathon results: working Rx

Alexander Chemeris alexander.chemeris at gmail.com
Thu Sep 13 11:03:51 UTC 2012

Hi all,

The fixed LMS control code is now at github, branch fairwaves/umtrx:

Note, that umtrx_ctrl.py command line interface has been extended and
slightly changed for more consistency:

--lms-pa-on and --lms-pa-off => --lms-set-tx-pa
--lms-set-vga1-gain => --lms-set-tx-vga1-gain
--lms-get-vga1-gain => --lms-get-tx-vga1-gain
--lms-set-vga2-gain => --lms-set-tx-vga2-gain
--lms-get-vga2-gain => --lms-get-tx-vga2-gain

New commands:

On Thu, Sep 13, 2012 at 2:40 AM, Alexander Chemeris
<alexander.chemeris at gmail.com> wrote:
> Hi all,
> Some good news for today. We've had a small fairwaves hackathon here
> in Moscow and we've done a good progress in UmTRX development. I'm
> quite exhausted, thus in short:
> 1. A software issue has been fixed in PLL tuning code. It works
> reliably now. Previously it didn't correctly handle edge cases when
> the best VCOCAP value was at the end of a range.
> 2. A software issue has been fixed in automatic LMS calibration code.
> Turns out a process described in the datasheet is not complete - you
> have read FAQ, question 4.7 for an amendment.
> 3. Now we correctly select Rx input. You have to change _two_
> registers to do that - 0x75 and 0x25. This wasn't obvious from the
> brief reading of the manual.
> 4. A hardware bug was fixed - RF diversity switch required a bias to
> work correctly. Luckily we decided to move the switch from the main
> board to a frontend in the rev2 of UmTRX. So we don't have to re-make
> the UmTRX schematics.
> Huge thanks to Andrey Sviyazov ("RF guy"), Andrew Karpenkov ("FPGA
> guy") and Srdjan Milenkovic ("remote LimeMicro guy") for going through
> all the issues.
> Fixes for the code will be pushed to github in the next few days after
> I clean it up.
> PS Another good news is that we should have first UmTRXv2 units on
> hands in the next few days, when we get them from customs. Can't wait
> to put my hands on them.
> --
> Regards,
> Alexander Chemeris.
> CEO, Fairwaves LLC / ООО УмРадио
> http://fairwaves.ru

Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио

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