Timer overflow behavior in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a timer variable that counts up to overflow.

Embedded C

volatile unsigned int timer = [1];

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

A1

B65535

C0

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Starting timer at max value causes immediate overflow.

Using negative values for unsigned timer.

The timer should start counting from 0 to overflow.

2fill in blank

medium

Complete the code to check if the timer has overflowed.

Embedded C

if (timer == [1]) {
    // Timer overflowed
}

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

A0

B-1

C65536

D65535

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for 65536 which is out of range for 16-bit.

Checking for zero which is the reset value after overflow.

The timer overflows when it reaches its maximum value 65535 for a 16-bit timer.

3fill in blank

hard

Fix the error in the overflow check condition.

Embedded C

if (timer [1] 65535) {
    // Handle overflow
}

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

A==

B>

C<

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' causes false positives.

Using '!=' triggers on all values except 65535.

The timer equals 65535 at overflow, so use '==' to check.

4fill in blank

hard

Fill both blanks to create a dictionary that maps timer values to overflow status.

Embedded C

const char* timer_status = (timer [1] 65535) ? "[2]" : "Running";

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

A==

BOverflow

C!=

DComplete

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' causes wrong status.

Using wrong string for overflow status.

Check if timer equals 65535 to mark overflow status.

5fill in blank

hard

Fill all three blanks to implement a function that resets the timer on overflow.

Embedded C

void reset_timer_if_overflow(unsigned int* timer) {
    if (*timer [1] [2]) {
        *timer = [3];
    }
}

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

A==

B65535

C0

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' causes reset at wrong times.

Resetting timer to max value instead of zero.

The function checks if timer equals 65535 and resets it to 0.