Datasheet

int adcin = A5;

int adcvalue = 0;

float mv_per_lsb = 3600.0F/1024.0F; // 10-bit ADC with 3.6V input range

void setup() {

Serial.begin(115200);

while ( !Serial ) delay(10); // for nrf52840 with native usb

}

void loop() {

// Get a fresh ADC value

adcvalue = analogRead(adcin);

// Display the results

Serial.print(adcvalue);

Serial.print(" [");

Serial.print((float)adcvalue * mv_per_lsb);

Serial.println(" mV]");

delay(100);

}

Advanced Example (12-bit, 3.0V Reference)

The original source for this code is included in the nRF52 BSP and can be viewed online here (https://adafru.it/zoe).

#include <Arduino.h>

#if defined ARDUINO_NRF52840_CIRCUITPLAY

#define PIN_VBAT A8 // this is just a mock read, we'll use the light sensor, so we can run

the test

#endif

uint32_t vbat_pin = PIN_VBAT; // A7 for feather nRF52832, A6 for nRF52840

#define VBAT_MV_PER_LSB (0.73242188F) // 3.0V ADC range and 12-bit ADC resolution = 3000mV/4096

#ifdef NRF52840_XXAA

#define VBAT_DIVIDER (0.5F) // 150K + 150K voltage divider on VBAT

#define VBAT_DIVIDER_COMP (2.0F) // Compensation factor for the VBAT divider

#else

#define VBAT_DIVIDER (0.71275837F) // 2M + 0.806M voltage divider on VBAT = (2M / (0.806M + 2M))

#define VBAT_DIVIDER_COMP (1.403F) // Compensation factor for the VBAT divider

#endif

#define REAL_VBAT_MV_PER_LSB (VBAT_DIVIDER_COMP * VBAT_MV_PER_LSB)

float readVBAT(void) {

float raw;

// Set the analog reference to 3.0V (default = 3.6V)

analogReference(AR_INTERNAL_3_0);

// Set the resolution to 12-bit (0..4095)

analogReadResolution(12); // Can be 8, 10, 12 or 14

// Let the ADC settle