https://devzone.nordicsemi.com/f/nordic-q-a/4936/about-adc-conversion-voltage-problemsI use direct input AIN2 pin battery 3.3v, the other pins are not connected to anything, I did not enter into ADC_IRQHandler,may ask about what the problem it this is my code : #define adc_PIN_NUMBER 1 NRF_ADC-&gt;INTENSET = ADC_INTENSET_END_Msk;en-USTelligent Community 13Mon, 29 Dec 2014 04:29:19 GMThttps://devzone.nordicsemi.com/thread/17419?ContentTypeID=1Mon, 29 Dec 2014 04:29:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:60dfd193-d869-4964-895c-898ae1e63e8cStefan Birnir Sverrisson<p>Hi</p> <p><a href="https://github.com/NordicSemiconductor/nrf51-ADC-examples/blob/master/rtc0_triggering_ADC_sample_from_GPIO_pin/main.c">This ADC example code</a> might give you some clues.</p><div style="clear:both;"></div>