Single channel ADC reading in Embedded C

Introduction

We use single channel ADC reading to convert one analog signal into a digital number so the microcontroller can understand it.

Reading temperature from a single sensor.

Measuring light intensity with one photoresistor.

Checking battery voltage level.

Reading a single joystick position.

Syntax

Embedded C

void ADC_Init(void);
uint16_t ADC_Read(void);

ADC_Init() sets up the ADC hardware before use.

ADC_Read() starts a conversion and returns the digital value.

Examples

Initialize ADC and read one value from the single channel.

Embedded C

ADC_Init();
uint16_t value = ADC_Read();

Continuously read the ADC value in a loop.

Embedded C

ADC_Init();
while(1) {
  uint16_t sensorValue = ADC_Read();
  // use sensorValue
}

Sample Program

This program initializes the ADC, simulates an analog input value, reads it, and prints the digital result.

Embedded C

#include <stdint.h>
#include <stdio.h>

// Simulated ADC hardware registers
volatile uint16_t ADC_DATA = 0;

void ADC_Init(void) {
    // Normally hardware setup code here
    // For simulation, do nothing
}

uint16_t ADC_Read(void) {
    // Simulate starting ADC conversion
    // Wait for conversion complete (simulated)
    // Return ADC data
    return ADC_DATA;
}

int main(void) {
    ADC_Init();
    ADC_DATA = 512; // Simulate analog input value
    uint16_t adcValue = ADC_Read();
    printf("ADC Reading: %u\n", adcValue);
    return 0;
}

Important Notes

ADC values depend on the reference voltage and resolution (e.g., 10-bit ADC gives values 0-1023).

Make sure to initialize the ADC before reading values.

Reading ADC may take some time; wait for conversion to finish if needed.

Summary

Single channel ADC reads one analog input and converts it to a digital number.

Initialize ADC hardware before reading values.

Use ADC_Read() to get the current analog value as a number.