nRF52820 COMP module

[sangjkim]

Hello,

I would like to use a single COMP I/O pin to compare the pin voltage to multiple references during run-time. 

To do this, I was planning on initializing the COMP driver by using nrfx_comp_init and setting the appropriate reference voltage and starting the measurement by calling nrfx_comp_start, and then finally sampling the pin by calling nrfx_comp_sample.

If the I/O pin voltage is below the reference voltage, I plan on uninitializing the COMP driver by calling nrfx_comp_uninit, then re-initializing the COMP driver with a different reference voltage and running the comparison.

Is this a good way to "measure" the pin voltage?  Since there is no SAADC in nRF52820, I figured that this is a decent enough way to get rough voltage measurements.

[Einar Thorsrud]

Hi,

The approach makes sense. I cannot say how good it is or if it is good enough for you, but it is probably the only possible approach for measuring pin voltage using the nRF52820 without additional HW. If this is not good enough, then you need to use either a different nRF52 device which includes the SAADC peripheral, or use some other external ADC or similar.

[sangjkim]

Understood.  Thank you for the feedback.

[Hardik.Harpal]

Did you able to do it?

[sangjkim]

I was able to use the method above to get a rough estimate of what the battery voltage is.  It is slow because I need to un-init -> set new threshold -> re-init and repeat the process as needed.  But it works for my specific needs.