https://devzone.nordicsemi.com/f/nordic-q-a/6536/measuring-vdd-with-adcHi, I am running the nRF51822 from a coin-cell. I need to measure the cell voltage. Until now, I have attached VDD to an ADC pin with a voltage divider and a capacitor (as described in the reference manual para 31.1.2). However, I later saw that accordingen-USTelligent Community 13Tue, 22 Nov 2016 12:06:17 GMThttps://devzone.nordicsemi.com/thread/22836?ContentTypeID=1Tue, 22 Nov 2016 12:06:17 GMT137ad170-7792-4731-bb38-c0d22fbe4515:03773c20-62eb-45d0-bf4f-bc35dff08986bjorn-spockeli<p>Yes, the SAADC of the nRF52 can measure VDD by setting <code>NRF_SAADC_INPUT_VDD</code> as the input pin. You can find examples for the nRF52 <a href="https://github.com/NordicSemiconductor/nRF52-ADC-examples">here</a>.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/22835?ContentTypeID=1Mon, 14 Nov 2016 19:14:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:288f96a0-e300-49da-9e15-4d10568d6746butch<p>The link is broken. Also, looking for same answer for nRF52. It seems that even though the nRF52 SAADC is not backward compatible with the nRF51 ADC, the SAADC can do the same thing: measure Vdd?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/22834?ContentTypeID=1Fri, 17 Apr 2015 06:49:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9504c367-c6fc-41da-9308-8027a923f87cStefan Birnir Sverrisson<p>Hi Uri</p> <p>You are correct. The easiest way to measure the supply voltage is to select VDD as input to the ADC, no input pin needed. This is done in <a href="https://github.com/NordicSemiconductor/nrf51-ADC-examples/blob/master/rtc0-triggering-adc-sample/main.c">this example</a>. Choose ADC_CONFIG_INPSEL_SupplyOneThirdPrescaling option as input to ADC and VBG as reference. Then the ADC range is 0V - 3.6V which is suitable to measure supply voltage from 3V battery.</p><div style="clear:both;"></div>