nRF52 SAADC Calibration Causes All Channels to Read The Same Analog Values

RE: nRF52 SAADC Calibration Causes All Channels to Read The Same Analog Values

Jørgen Holmefjord — Mon, 18 Mar 2019 10:26:14 GMT

This is exactly what happens with PAN-86. The symptoms reads: "The first sample in the result buffer is incorrect, and will be present although the SAMPLE task has never been issued." You need to implement the Workaround described in the errata to make sure you do not get the extra sample in the buffer after calibration. You will not see any other issues with sampling after calibration, this issue will only be visible as an additional sample in the buffer, exactly how you describe it.

RE: nRF52 SAADC Calibration Causes All Channels to Read The Same Analog Values

Jennifer — Wed, 27 Feb 2019 16:00:57 GMT

Hi I just checked the thread and I'm a bit confused about which part you are referring to. Is it the PAN-86: SAADC: Triggering START task after offset calibration may write a sample to RAM. ? I don't have any problem with the ADC triggering after calibration. They trigger at the right intervals set. However, the next reading after calibration is just wrong for the second ADC channel since it basically gives me the same reading as channel 0 reading.

RE: nRF52 SAADC Calibration Causes All Channels to Read The Same Analog Values

run_ar — Wed, 27 Feb 2019 12:38:46 GMT

Hi,

Can you please check if this is related: https://devzone.nordicsemi.com/f/nordic-q-a/29806/nrf52832-sdk14---saadc-calibration-issues

Thanks,