Interrupt priority levels in Embedded C - Mini Project: Build & Apply

Interrupt Priority Levels

📖 Scenario: You are working on a simple embedded system that handles multiple interrupts. Each interrupt has a priority level. Higher priority interrupts should be handled before lower priority ones.Imagine you have three interrupts: Timer, UART, and ADC. You want to assign priority levels to them so the system knows which interrupt to handle first.

🎯 Goal: Build a small program that sets up interrupt priority levels using variables and then prints the priority order.

📋 What You'll Learn

Create variables for three interrupts: timer_priority, uart_priority, and adc_priority with exact integer values.

Create a variable highest_priority to hold the highest priority value.

Use conditional statements to find which interrupt has the highest priority.

Print the name of the interrupt with the highest priority.

💡 Why This Matters

🌍 Real World

Embedded systems often have multiple interrupts. Setting priority levels helps the system decide which interrupt to handle first, ensuring important tasks get immediate attention.

💼 Career

Understanding interrupt priorities is essential for embedded software developers working on microcontrollers, real-time systems, and hardware interfacing.

1

Set interrupt priority levels

Create three integer variables called timer_priority, uart_priority, and adc_priority with values 2, 1, and 3 respectively.

Embedded C

# Create interrupt priority variables
// Your code here

Need a hint?

Use int to declare variables and assign the exact values.

2

Create a variable for highest priority

Create an integer variable called highest_priority and set it to 0.

Embedded C

int timer_priority = 2;
int uart_priority = 1;
int adc_priority = 3;

// Create highest_priority variable
// Your code here

Need a hint?

Initialize highest_priority to zero before comparing.

3

Find the highest priority interrupt

Use if statements to compare timer_priority, uart_priority, and adc_priority. Set highest_priority to the highest value among them.

Embedded C

int timer_priority = 2;
int uart_priority = 1;
int adc_priority = 3;

int highest_priority = 0;

// Compare priorities and set highest_priority
// Your code here

Need a hint?

Check each priority and update highest_priority if the current one is greater.

4

Print the highest priority interrupt

Use if statements to check which interrupt has the highest_priority value. Then print the exact text "Highest priority interrupt: TIMER", "Highest priority interrupt: UART", or "Highest priority interrupt: ADC" accordingly using printf.

Embedded C

int timer_priority = 2;
int uart_priority = 1;
int adc_priority = 3;

int highest_priority = 0;

if (timer_priority > highest_priority) {
    highest_priority = timer_priority;
}
if (uart_priority > highest_priority) {
    highest_priority = uart_priority;
}
if (adc_priority > highest_priority) {
    highest_priority = adc_priority;
}

// Print the highest priority interrupt
// Your code here

Need a hint?

Use printf to print the exact text with a newline. Compare highest_priority to each interrupt priority.