LPF Bandwidth Tuning with LMS6002

Alexander Chemeris alexander.chemeris at gmail.com
Mon Oct 8 23:50:03 UTC 2012


Hi Gillian,

So, I see you've ported umtrx_lms.py to the board you're using? If you
want to share your port with the community, I'm happy to merge your
changes to our git. I think we could even create a separate git repo
for umtrx_lms.py in this case.

Regarding your question. It might help if you post here output from
umtrx_lms.py and umtrx_ctrl.py at the maximum verbosity (say, 10). The
value is set at the top of the files for now. In general, I think you
should check that you've enabled proper blocks in LMS and enabled SPI
clocks for them. If this doesn't work - check with the manufacturer of
your board. I have no idea which board do you use, but the
manufacturer may have intentionally or unintentionally break tuning
abilities of the chip,

On Mon, Oct 8, 2012 at 3:51 PM, Gillian Seed <gillian.seed at outlook.com> wrote:
> Hi,
> I'm having a problem while trying to do a LPF Bandwidth tuning as described
> in a Programming and Calibration guide page 40, figure 4.5 and on
> https://github.com/chemeris/UHD-Fairwaves/blob/fairwaves/umtrx/host/utils/umtrx_lms.py#L433.
> Currently it seems to always fail when it's trying to find the VCOCAP value.
> I'm only getting Low printed before it fails. I was wondering why it takes a
> 320MHz frequency, because it's not described anywhere in the documents,
> could I try to do a bandwidth tuning with some other frequency as well? I'm
> running my code in a following order
> (http://lists.osmocom.org/pipermail/umtrx/2012-July/000075.html),
>
> Example setup for ARFCN 925:
>
> Initialization and auto-calibration:
>   ./umtrx_lms.py --lms 1 --lms-init
>   ./umtrx_lms.py --lms 1 --lms-tx-enable 1
>   ./umtrx_lms.py --lms 1 --lms-rx-enable 1
>   ./umtrx_lms.py --lms 1 --pll-ref-clock 26e6 --lpf-bandwidth-code
> 0x0f --lms-auto-calibration
>
> RX LNA and RXVGA2 selection and gain control
>   ./umtrx_lms.py --lms 1 --reg 0x75 --data 0xf0
>   ./umtrx_lms.py --lms 1 --reg 0x65 --data 10
>
> TX LPF control
>   ./umtrx_lms.py --lms 1 --reg 0x34 --data 0x3e
>
> LO leakage cancellation (calibration data values may vary)
>   ./umtrx_lms.py --lms 1 --reg 0x42 --data 0x67
>   ./umtrx_lms.py --lms 1 --reg 0x43 --data 0x89
>
> TX/RX PLL charge pump current
>   ./umtrx_lms.py --lms 1 --reg 0x16 --data 0x93
>
> Tuning
>   ./umtrx_lms.py --lms 1 --lms-rx-pll-tune 925.2e6
>   ./umtrx_lms.py --lms 1 --lms-tx-pll-tune 880.2e6
>
> TXVGA2 gain to max and enable PA
>   ./umtrx_lms.py --lms 1 --reg 0x45 --data 0xc8
>   ./umtrx_lms.py --lms 1 --lms-pa-on 2
>
>



-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru




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