Why watchdog timer is needed in Embedded C - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the watchdog timer.

Embedded C

WDTCTL = [1];

Drag options to blanks, or click blank then click option'

AWDTPW | WDTTMSEL

BWDTPW | WDTHOLD

CWDTPW | WDTSSEL

DWDTPW | WDTCNTCL

Attempts:

3 left

💡 Hint

Common Mistakes

Using WDTHOLD stops the watchdog timer instead of starting it.

The watchdog timer control register needs to clear the counter to start the timer properly. WDTCNTCL does this.

2fill in blank

medium

Complete the code to reset the watchdog timer inside the main loop.

Embedded C

while(1) {
    [1];
    // main program tasks
}

Drag options to blanks, or click blank then click option'

AWDTCTL = WDTPW | WDTSSEL

BWDTCTL = WDTPW | WDTHOLD

CWDTCTL = WDTPW | WDTCNTCL

DWDTCTL = WDTPW | WDTTMSEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using WDTHOLD inside the loop stops the watchdog timer, defeating its purpose.

Resetting the watchdog timer regularly prevents it from resetting the system. WDTCNTCL clears the timer count.

3fill in blank

hard

Fix the error in the watchdog timer initialization code.

Embedded C

WDTCTL = [1]; // Start watchdog timer

Drag options to blanks, or click blank then click option'

AWDTPW | WDTHOLD

BWDTPW | WDTCNTCL

CWDTPW | WDTHOLD | WDTCNTCL

DWDTPW

Attempts:

3 left

💡 Hint

Common Mistakes

Including WDTHOLD stops the watchdog timer immediately.

WDTHOLD stops the watchdog timer. To start and clear it, use WDTCNTCL with the password WDTPW.

4fill in blank

hard

Fill both blanks to create a dictionary of task names and their watchdog reset status.

Embedded C

const char* tasks[] = {"Sensor", "Motor", "Display"};
int resetStatus[] = {1, 0, 1};
for(int i = 0; i < 3; i++) {
    printf("Task: %s, Reset: %d\n", [1], [2]);
}

Drag options to blanks, or click blank then click option'

Atasks[i]

BresetStatus[i]

Ctasks

DresetStatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using the array name without index prints the pointer address.

To print each task and its reset status, use the indexed elements tasks[i] and resetStatus[i].

5fill in blank

hard

Fill all three blanks to implement a watchdog timer reset check with condition.

Embedded C

if([1] [2] 1000) {
    [3] = 0; // Reset watchdog timer counter
}

Drag options to blanks, or click blank then click option'

AwatchdogCounter

B>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than operator reverses the logic.

The code checks if watchdogCounter is greater than 1000, then resets watchdogCounter to 0.