ADC interrupt-driven reading in Embedded C - Mini Project: Build & Apply

ADC Interrupt-Driven Reading

📖 Scenario: You are working on a small embedded system that reads analog sensor values using an ADC (Analog-to-Digital Converter). Instead of waiting for the ADC to finish, you want to use interrupts to get the reading when it's ready. This way, your program can do other tasks while waiting.

🎯 Goal: Build a simple program that sets up an ADC, enables its interrupt, and reads the converted value inside the interrupt handler. Then, print the ADC value in the main loop.

📋 What You'll Learn

Create a variable to store the ADC value

Set up an ADC interrupt enable flag

Write an interrupt handler to read the ADC value

Print the ADC value in the main loop

💡 Why This Matters

🌍 Real World

Embedded systems often use ADC interrupts to read sensors without blocking the main program.

💼 Career

Understanding interrupt-driven ADC reading is important for embedded firmware developers working on microcontrollers.

1

Create a variable to store the ADC value

Create a global variable called adc_value of type volatile unsigned int and initialize it to 0.

Embedded C

# Your code here

Need a hint?

Use volatile because the variable changes inside an interrupt.

2

Enable ADC interrupt flag

Create a variable called adc_interrupt_enabled of type int and set it to 1 to simulate enabling the ADC interrupt.

Embedded C

volatile unsigned int adc_value = 0;
# Your code here

Need a hint?

This variable simulates the ADC interrupt enable flag.

3

Write the ADC interrupt handler

Write a function called ADC_IRQHandler that simulates the ADC interrupt handler. Inside it, assign adc_value to 1234 to simulate reading the ADC result.

Embedded C

volatile unsigned int adc_value = 0;
int adc_interrupt_enabled = 1;

// Your code here

Need a hint?

This function simulates the interrupt setting the ADC value.

4

Print the ADC value in main loop

Write a main function that calls ADC_IRQHandler() if adc_interrupt_enabled is 1, then prints the adc_value using printf.

Embedded C

volatile unsigned int adc_value = 0;
int adc_interrupt_enabled = 1;

void ADC_IRQHandler(void) {
    adc_value = 1234;
}

// Your code here

Need a hint?

This simulates the main program reacting to the ADC interrupt and printing the value.