Window watchdog concept in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable the window watchdog timer.

Embedded C

WWDG->CR = [1];

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

A0x7F

B0x40

C0x80

D0x00

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x00 disables the watchdog.

Using 0x7F sets the counter but does not enable it.

The control register (CR) is set with 0x80 to activate the watchdog counter.

2fill in blank

medium

Complete the code to set the window value for the watchdog timer.

Embedded C

WWDG->CFR = ([1] << 0);

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

A0x80

B0x7F

C0x40

D0x3F

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x7F sets the window too high, disabling the window effect.

Using 0x80 sets a bit outside the window value field.

The window value is set by writing 0x3F to the lower 7 bits of the CFR register.

3fill in blank

hard

Fix the error in the code to refresh the watchdog counter correctly.

Embedded C

WWDG->CR = [1];

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

A0x7F

B0x80

C0x3F

D0x40

Attempts:

3 left

💡 Hint

Common Mistakes

Writing 0x3F lowers the counter incorrectly.

Writing 0x80 disables the watchdog.

Refreshing the watchdog requires writing 0x7F to the CR register to reset the counter.

4fill in blank

hard

Fill both blanks to configure the prescaler and enable the watchdog interrupt.

Embedded C

WWDG->CFR = ([1] << 7) | (1 << [2]);

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

A3

B6

C5

D7

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong bit positions disables features.

Confusing prescaler and interrupt bits.

The prescaler is set by shifting 3 to bit 7, and the interrupt enable is bit 6.

5fill in blank

hard

Fill all three blanks to initialize the watchdog with prescaler, window, and refresh.

Embedded C

WWDG->CFR = ([1] << 7) | [2];
WWDG->CR = [3];

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

A2

B0x3F

C0x7F

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing prescaler and window values.

Using refresh value outside allowed range.

Prescaler set to 4 (shifted to bit 7), window set to 0x3F, and refresh counter set to 0x7F.