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BladeRF A4 - Clock Select Issue

Posted: Wed Mar 06, 2019 7:16 am
by slaw1982
I am trying to setup two BladeRF A4 boards that share a clock. The first BladeRF uses a 10MHz input to REFIN and then is configured to output the 38.4MHz clock via CLKOUT. Everything seems to work fine with this setup.

The second board i try to setup to accept the clock from the first board via the CLKIN pin using the:
set clock_sel external

The system pauses for a few seconds before returning an error:

[ERROR @ host/libraries/libbladeRF/src/backend/usb/nios_access.c:78]
Failed to receive NIOS II response: An unexpected error occured
[ERROR @ host/libraries/libbladeRF/src/board/bladerf2/bladerf2.c:3487]
bladerf_set_clock_select: dev->backend->config_gpio_write(dev, gpio) failed:
An unexpected error

Any ideas why this is failing?

Thanks

Re: BladeRF A4 - Clock Select Issue

Posted: Tue Mar 19, 2019 1:37 am
by robert.ghilduta
It appears that the second slave bladeRF micro may not be receiving a clock.
Can you please run bladeRF-cli with --verbosity=verbose? Are you sure CLKOUT is enabled on the master? What kind of cable are you using? Perhaps trying a shorter, less lossy UFL might help as well.