Sample battery voltage via VDDHDIV5 in zephyr with NRF52840

[samm]

Hi,

I am currently developing an application for the NRF52840 using a custom pcb powered through the VDDH pin using a 4.2v lithium ion battery. Part of my application requires me to monitor the battery voltage, and I was previously able to achieve this using the NRF SDK and sampling VDDHDIV5 as per the below thread:

https://devzone.nordicsemi.com/f/nordic-q-a/46513/how-to-measure-battery-voltage-4-2v-3-0v-without-external-resistors-on-nrf52840

Recently however, I have switched my project over to using Zephyr and was unable to find any example showing how to do the same thing. I see examples for sampling the 8 ADC channels but not VDDHDIV5. Is this possible to achieve this using Zephyr or will I need to update the hardware to use a voltage divider and sample using one of the eight ADC channels?

Thanks in advance!

[haakonsh]

Use the nrfx driver in NCS\modules\hal\nordic\nrfx\drivers\src\nrfx_saadc.c. 

#include <nrfx.h>
#include <nrfx_saadc.h>

Enable the SAADC peripheral in configs:
CONFIG_SAADC_NRFX= y

[samm]

Thanks for your response. I was able to get it working using the nrf/battery example on github with a few small tweaks.

Cheers,

Sam.