Battery voltage reading

[Nilon123456789]

I am wondering how the battery voltage reading works, since it's using adc AIN2 that is not connected.

[rbaron]

Hey @Nilon123456789,

You can see here that we use channel 2 for battery measurement, and it's configured to use the VDD pin as input (via the NRF_SAADC_VDD value). Channel 2 refers to the SAADC channel, and it's a different thing from the AIN2 pin (which is not used for this). You can refer to section 6.23 on the datasheet for this:

[Nilon123456789]

Alright thanks

[Nilon123456789]

A question just popped in my head, why do you define in the zephyr,user the io-channel adc 2, if your not using it. Is it just to be able to fetch the config of channel 2?

[rbaron]

I'm not sure I follow. We do use it in adc.c:37. This is the same strategy used in this Zephyr sample.