4.Digital-Analog Converter

The usage of DAC

The purpose of the DAC is the opposite of that of the ADC. The DAC converts a digital signal into an analog signal for output.

Remember the music when NyBoard is turned on? It is using PWM to make music sound which uses high-speed switching to adjust the duty cycle to output voltage.

Compared with PWM, the DAC will directly output the voltage without calculating the duty cycle. ESP32 integrates a 2-channel 8-bit DAC with a value of 0-255. The voltage range is 0-3.3V. Therefore, the formula for calculating the output voltage of the DAC is as follows:

DAC=intTargetV/3.3V255DAC=(int)TargetV/3.3V∗255

The demo is as follows:

#define DAC1 25
void setup() {
}
void loop() {
// 8bit DAC, 255 = 3.3V, 0 = 0.0V
for(int i = 0; i < 255; i++){
dacWrite(DAC1, i);
delay(10);
}
}