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Code: Select all

#include "esp_efuse.h"
#include "soc/efuse_reg.h"
#include "esp_efuse_table.h"
#include "soc/efuse_periph.h"
#include "esp_err.h"
#include "esp_adc_cal.h"

#define VREF_FORMAT                     0
#define VREF_REG                        EFUSE_BLK0_RDATA4_REG
#define VREF_MASK                       0x1F
#define VREF_STEP_SIZE                  7
#define VREF_OFFSET                     1100

static inline int decode_reg_bits(uint32_t bits, uint32_t mask, bool is_twos_compl)
{
    int ret;
    if (bits & (~(mask >> 1) & mask)) {      //Check sign bit (MSB of mask)
        //Negative
        if (is_twos_compl) {
            ret = -(((~bits) + 1) & (mask >> 1));   //2's complement
        } else {
            ret = -(bits & (mask >> 1));    //Sign-magnitude
        }
    } else {
        //Positive
        ret = bits & (mask >> 1);
    }
    return ret;
}

static uint32_t read_efuse_vref_reg(void)
{
    //eFuse stores deviation from ideal reference voltage
    uint32_t ret = VREF_OFFSET;       //Ideal vref
    uint32_t bits = REG_GET_FIELD(VREF_REG, EFUSE_ADC_VREF);
    ret += decode_reg_bits(bits, VREF_MASK, VREF_FORMAT) * VREF_STEP_SIZE;
    return ret;     //ADC Vref in mV
}


void read_efuse_values(){
    uint8_t mac[6];
    ESP_ERROR_CHECK(esp_efuse_read_field_blob(ESP_EFUSE_MAC_FACTORY, &mac, sizeof(mac) * 8));
    printf("1. read MAC address: %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);

    uint32_t efuse_vref = read_efuse_vref_reg();
    printf("2. ADC_VREF from eFuse: %u mV\n", efuse_vref);
}

Code: Select all

#include "esp_adc_cal.h"

void setup() {
Serial.begin(115200);
while (!Serial) {}

  //Read eFuse Voltage Refference
  esp_adc_cal_characteristics_t adc_chars;                                                        //declaring ADC calibration variable adc_chars
  esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, 1100, &adc_chars);      //characterizing the ADC calibration function ADC_UNIT_1 or ADC_UNIT_2
  Serial.println(); Serial.print("eFuse-Vref:"); Serial.print(adc_chars.vref); Serial.println();  //reading the actual internal refference voltage
}

void loop() {
}

Code: Select all

#include <soc/efuse_reg.h>

void setup() {
Serial.begin(115200);
while (!Serial) {}

//Read all registers of eFuse Block 0 
uint32_t blk0reg0 = REG_READ(EFUSE_BLK0_RDATA0_REG), blk0reg1 = REG_READ(EFUSE_BLK0_RDATA1_REG), blk0reg2 = REG_READ(EFUSE_BLK0_RDATA2_REG), blk0reg3 = REG_READ(EFUSE_BLK0_RDATA3_REG), 
         blk0reg4 = REG_READ(EFUSE_BLK0_RDATA4_REG), blk0reg5 = REG_READ(EFUSE_BLK0_RDATA5_REG), blk0reg6 = REG_READ(EFUSE_BLK0_RDATA6_REG); //blk0reg7 = REG_READ(EFUSE_BLK0_RDATA7_REG) did not work

  //Print all registers of eFuse Block 0
  Serial.println(); Serial.println();
  Serial.print("Block 0 non HEX: "); Serial.print(blk0reg0); Serial.print(blk0reg1); Serial.print(blk0reg2);
  Serial.print(blk0reg3); Serial.print(blk0reg4); Serial.print(blk0reg5); Serial.print(blk0reg6); Serial.println(); //Serial.print(blk0reg7)

  //HEX Print all registers of eFuse Block 0
  Serial.println("Block 0 HEX:");
  Serial.print("Block 0, Register 0: "); Serial.println(blk0reg0, HEX);
  Serial.print("Block 0, Register 1: "); Serial.println(blk0reg1, HEX);
  Serial.print("Block 0, Register 2: "); Serial.println(blk0reg2, HEX);
  Serial.print("Block 0, Register 3: "); Serial.println(blk0reg3, HEX);
  Serial.print("Block 0, Register 4: "); Serial.println(blk0reg4, HEX);
  Serial.print("Block 0, Register 5: "); Serial.println(blk0reg5, HEX);
  Serial.print("Block 0, Register 6: "); Serial.println(blk0reg6, HEX);
  //Serial.print("Block 0, Register 7: "); Serial.println(blk0reg7, HEX);
}

void loop() {
}

Code: Select all

#include <driver/adc.h>        //ADC driver or include esp_adc_cal.h Both work

void setup() {
  esp_err_t status = adc_vref_to_gpio(ADC_UNIT_2, GPIO_NUM_26);
  if (status == ESP_OK) {
        printf("\nv_ref routed to desired GPIO\n");
  } else {
        printf("failed to route v_ref\n");
    }
}

void loop() {
}