How to read in a 4.2V battery reading on a nRF51822

RE: How to read in a 4.2V battery reading on a nRF51822

Martin Lesund — Wed, 14 Feb 2018 14:23:23 GMT

3.6V is max even if you are using a higher reference on Vbg.
A proposal can be to use a voltage divider from the battery source and into the ADC

RE: How to read in a 4.2V battery reading on a nRF51822

tyler — Wed, 07 Feb 2018 15:03:31 GMT

Ok that makes sense. I happen to have a 3.3V voltage regulator on the board. Could I use this as a reference for the battery instead of the 1.2V Vbg for the same 4.2V battery?

RE: How to read in a 4.2V battery reading on a nRF51822

Martin Lesund — Wed, 07 Feb 2018 14:30:36 GMT

I recommend you to stay in the recommended voltage range.

If you go outside this specter it can result in unwanted behaviour.

RE: How to read in a 4.2V battery reading on a nRF51822

tyler — Tue, 06 Feb 2018 17:40:51 GMT

Ok that blog is very useful. I noticed that the maximum voltage the nRF51822 can read is 3.6V after a 1/3 prescaling with a reference to Vbg. What I am wondering is if I put in a higher voltage (say 4V) will it actually damage the chip or will it just read the wrong voltage value?

RE: How to read in a 4.2V battery reading on a nRF51822

Martin Lesund — Tue, 06 Feb 2018 09:53:10 GMT

This Blog should also be helpful for you

RE: How to read in a 4.2V battery reading on a nRF51822

Martin Lesund — Tue, 06 Feb 2018 07:52:40 GMT

Hi Tyler,

Please take a look at the answer in this thread. I think that should answer your question.

(updated links: Reference manual v3.0.1 Chapter 31 and Product specification v3.3, Chapter 7)