nRF52832 SAADC AIN3 bad readings

[ColM]

Using nRF52832 I am collecting from 8 SAADC channels using example ble_app_uart__saadc_timer_driven__scan_mode as a guide. AIN3 (P0.05) gives incorrect results. Because P0.05 is nominally UART RTS I have cut sb22 and sb13 as suggested in the documentation, set HWFC false in pca10040.h but readings are still incorrect. For example, grounding P0.05 does not drop it to zero as it does for the other channels.

[Jørgen Holmefjord]

Are you sure the pin is not configured for use with any other peripheral? Could you provide an example of what you are reading and what you expect? Can you upload your code for debugging? Also, if you cut SB13, you have disconnected the pin from the pin header. Are you sure you have the input connected to the pin? If not it will be left floating, giving you incorrect readings.

[ColM]

Thank you. Restoring SB13 fixed the problem and now all 8 channels are sampling nicely.