Re: [Discuss OpenCPI] Fwd: Fwd: AD9361 ADC/DAC Test Applications

From: Brian Padalino <bpadalino_at_gmail.com>
Date: Fri, 03 Apr 20 15:08:16 -0400

On Fri, Apr 3, 2020 at 2:45 PM Davis Hoover <dhoover_at_geontech.com> wrote:

> The AD9361 BIST PRBS mode utilizes an on-AD9361 LFSR. The OpenCPI
> applications for both the AD9361 BIST PRBS, which verifies the ADC
> interface, and the AD9361 BIST loopback, which verifies the DAC and ADC
> interface, each utilize the same bitwise LFSR verification on the .out
> file(s).
>

So this is where the confusion comes from. There is a mode which runs such
that the data_src is set to 'mode=lfsr', the spec is here:


https://gitlab.com/opencpi/opencpi/-/blob/7b689ca89f329f1845290626ab95647946877082/projects/assets/components/misc_comps/specs/data_src-spec.xml#L48

The script is here:


https://gitlab.com/opencpi/opencpi/-/blob/7b689ca89f329f1845290626ab95647946877082/projects/assets/applications/ad9361_dac_test/scripts/AD9361_BIST_loopback.sh#L249

And it's called here:


https://gitlab.com/opencpi/opencpi/-/blob/7b689ca89f329f1845290626ab95647946877082/projects/assets/applications/ad9361_dac_test/scripts/ad9361_dac_test.sh#L147

But the PRBS test is called here:


https://gitlab.com/opencpi/opencpi/-/blob/7b689ca89f329f1845290626ab95647946877082/projects/assets/applications/ad9361_dac_test/scripts/ad9361_dac_test.sh#L86

So if I comment out the PRBS test, and only run the loopback test - things
work spectacularly great - 0% BER.

But the PRBS test runs with 30% BER.

I suppose I should have clarified specifically I am using the loopback test
when it shows 0% BER.

Does this help shed any light on anything, especially regarding my
confusion? I would have thought the loopback test would fail miserably if
the PRBS test also does. But this is not the case.

Thanks,
Brian


Received on Fri Apr 03 2020 - 19:08:16 CDT

This archive was generated by hypermail 2.3.0 : Fri Jun 05 2026 - 08:45:25 CDT