FireBeetle 2 ESP32 C6 Development Board _ADC Module Test

尹小舟

FireBeetle 2 ESP32 C6 Development Board _ADC Module Test [Copy link]

 

This time, let’s test the ADC of ESP32

1. MCU uses 3.3V power supply

2. Use a potentiometer to provide a signal

3. Test the code

void setup() {
  // initialize serial communication at 115200 bits per second:
  Serial.begin(115200);
  
  //set the resolution to 12 bits (0-4095)
  analogReadResolution(12);
}

void loop() {
  // read the analog / millivolts value for pin 2:
  int analogValue = analogRead(2);
  int analogVolts = analogReadMilliVolts(2);
  
  // print out the values you read:
  Serial.printf("ADC analog value = %d\n",analogValue);
  Serial.printf("ADC millivolts value = %d\n",analogVolts);
  
  delay(100);  // delay in between reads for clear read from serial
}

4. Test situation

Voltage value	AD value
3.3	3344
2.38	2382
2.03	2033
1.70	1701
1.00	1002

This value is very strange. 3,3V should be 4095, why is it 3344? It seems to have been transformed. Does anyone know what's going on?

dcexpert

Is the ADC attenuation set?

尹小舟

dcexpert posted on 2024-5-8 11:27 Is the ADC attenuation set?

I haven't used attenuation on Arduino either, is there a setting for this?

尹小舟

I found this function. Is it related to it? How to use it?

尹小舟

Strange, strange

dcexpert

The ADC of ESP32 is slightly different from other MCUs and a little more complicated. There seems to be a calibration function for accuracy.

damiaa

Yin Xiaozhou published on 2024-5-8 13:40 I found this function. Is it related to it? How to use it?

It should be that if this is not set, the default is DB_11. Although it can only test below 3.3V, the reference is 3.9V. In this way, 3.3V is more than 3000.