How can I read out the actual value of the power supply, using the low power comparator?

[Giannis Anastasopoulos]

Dear all,

I need to read out the voltage of the battery that supplies my nrf52. From what I have read I see that there are 2 options: LPCOMP and ADC.

Due to restrictions that I have because of my hardware, I cannot add any exteranl components in order to add the voltage divider. So I need to use the LPCOMP.

I have checked the SDK example, but I don't see how to actually read out the value. Searching around has only revealed to me there is a way to trigger an event when the supply voltage falls under a certain value. But what do I need to do in order to measure the value of the supply voltage?

[awneil]

Giannis Anastasopoulos said:

I don't see how to actually read out the value

The "LPCOMP" is a comparator - so it does not give you a "read out of the voltage"

A comparator just tells you that the input is above or below the reference.

Giannis Anastasopoulos said:

I cannot add any exteranl components in order to add the voltage divider.

If your battery voltage exceeds the allowable input pin voltage, then you will still need a divider - whether you use the comparator or the ADC

[Giannis Anastasopoulos]

So, from what I understand, I can simply read the voltage directly from the pin, without any voltage divider, as long as my supplied voltage is less than 3.3V, correct?

[awneil]

Check the Product Specification for the actual limit (which is also related to VDD) - as long as you don't exceed that, you're OK.

You may also need to adjust the ADC gain so as not to exceed its internal input range