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Always getting large/small ADC overrange and digital saturation in TDD mode

Question asked by njp on Jan 27, 2015
Latest reply on Mar 18, 2015 by mhennerich

I'm running the AD9361 in TDD mode (adi-fmcomm2.dtsi is attached) and I notice that in Manual gain mode the large and small ADC overranges flags and digital saturation flag are set on every IQ collect, even if the gain is 1dB. The actual data looks OK though.


I was able to fix this by commenting out the following two following two SPI writes in ad9361.c (also attached)

  • in function ad9361_ensm_force_state: ad9361_spi_write(spi, REG_ENSM_CONFIG_1, TO_ALERT | FORCE_ALERT_STATE);
  • in function ad9361_ensm_restore_prev_state : ad9361_spi_write(spi, REG_ENSM_CONFIG_1, TO_ALERT | FORCE_ALERT_STATE);


I'm frankly not sure if commenting out only one or both of these lines is required to fix the flags issue. However, with the change the flags seem to be set when appropriate.


FYI I noticed this many commits ago but am posting about it now for others. I'm up to date with this commit: drivers/iio/adc/ad9361:Fix permissions on filter_fir_config sysfs bin at... · 0494ffb · analogdevicesinc/linux · GitHub