Window watchdog concept in Embedded C - Mini Project: Build & Apply

Window Watchdog Concept in Embedded C

📖 Scenario: You are working on a simple embedded system that needs to monitor if a task is running correctly within a specific time window. If the task does not reset the watchdog timer in time, the system should detect this and take action.

🎯 Goal: Build a simple program that simulates a window watchdog timer. You will create variables to represent the timer, configure the allowed time window, implement the logic to check if the timer is reset within the window, and finally print the status of the watchdog.

📋 What You'll Learn

Create variables to represent the watchdog timer and window limits

Configure the allowed time window for resetting the watchdog

Implement logic to check if the watchdog is reset within the window

Print the watchdog status indicating if it is OK or if a reset is needed

💡 Why This Matters

🌍 Real World

Window watchdog timers are used in embedded systems to ensure tasks run correctly within specific time limits, preventing system crashes.

💼 Career

Understanding watchdog timers is important for embedded software developers working on reliable and safe hardware systems.

1

Create initial watchdog timer variables

Create an integer variable called watchdog_timer and set it to 0. Also create two integer variables called window_start and window_end and set them to 5 and 10 respectively.

Embedded C

# Create variables for watchdog_timer, window_start, and window_end
# Your code here

Need a hint?

Use simple integer variables and assign the exact values as instructed.

2

Configure the reset time for the watchdog

Create an integer variable called reset_time and set it to 7. This represents the time when the watchdog is reset.

Embedded C

int watchdog_timer = 0;
int window_start = 5;
int window_end = 10;

// Create reset_time variable
// Your code here

Need a hint?

Just add one more integer variable with the exact name and value.

3

Implement the window watchdog check logic

Write an if statement that checks if reset_time is greater than or equal to window_start and less than or equal to window_end. If true, set watchdog_timer to 0 to simulate a successful reset. Otherwise, set watchdog_timer to 1 to indicate a reset failure.

Embedded C

int watchdog_timer = 0;
int window_start = 5;
int window_end = 10;
int reset_time = 7;

// Add if statement to check reset_time within window
// Your code here

Need a hint?

Use a simple if-else to check if reset_time is inside the allowed window.

4

Print the watchdog status

Write a printf statement that prints "Watchdog status: OK" if watchdog_timer is 0, otherwise print "Watchdog status: RESET NEEDED".

Embedded C

int watchdog_timer = 0;
int window_start = 5;
int window_end = 10;
int reset_time = 7;

if (reset_time >= window_start && reset_time <= window_end) {
    watchdog_timer = 0;
} else {
    watchdog_timer = 1;
}

// Print watchdog status
// Your code here

Need a hint?

Use printf and check the watchdog_timer value to print the correct message.