Generating precise delays with timers in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the timer.

Embedded C

TIM2->CR1 |= [1];

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ATIM_CR1_DIR

BTIM_CR1_CEN

CTIM_CR1_UDIS

DTIM_CR1_OPM

Attempts:

3 left

💡 Hint

Common Mistakes

Using TIM_CR1_UDIS disables the timer update event.

Using TIM_CR1_DIR changes the counting direction.

Using TIM_CR1_OPM sets one pulse mode instead of starting timer.

Setting TIM_CR1_CEN bit starts the timer counter.

2fill in blank

medium

Complete the code to set the prescaler value for the timer.

Embedded C

TIM3->PSC = [1] - 1;

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Aprescaler_value

Bcounter_value

Cdelay_time

Dtimer_frequency

Attempts:

3 left

💡 Hint

Common Mistakes

Using delay_time instead of prescaler_value.

Setting counter_value in PSC register.

Confusing timer_frequency with prescaler_value.

The prescaler divides the timer clock frequency by (PSC+1).

3fill in blank

hard

Fix the error in the code to wait until the timer update event occurs.

Embedded C

while (!(TIM4->SR & [1])) {}

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ATIM_SR_CC1IF

BTIM_SR_TIF

CTIM_SR_CC2IF

DTIM_SR_UIF

Attempts:

3 left

💡 Hint

Common Mistakes

Using capture/compare flags instead of update flag.

Using undefined or incorrect flag bits.

TIM_SR_UIF is the update interrupt flag indicating timer overflow.

4fill in blank

hard

Fill both blanks to configure the timer for a 1s delay assuming 16MHz clock.

Embedded C

TIM5->PSC = [1] - 1;
TIM5->ARR = [2] - 1;

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A16000

B1000

C1600

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping prescaler and ARR values.

Using wrong values that don't match clock frequency.

Prescaler divides 16MHz to 1kHz (16000), ARR counts 1000 ticks for 1s delay.

5fill in blank

hard

Fill all three blanks to create a delay function using TIM6 with prescaler and auto-reload values.

Embedded C

void delay_ms(uint16_t ms) {
    TIM6->PSC = [1] - 1;
    TIM6->ARR = [2] * ms - 1;
    TIM6->EGR = [3];
    TIM6->SR = 0;
    TIM6->CR1 |= TIM_CR1_CEN;
    while (!(TIM6->SR & TIM_SR_UIF)) {}
}

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

A16000

B1

CTIM_EGR_UG

D1000

Attempts:

3 left

💡 Hint

Common Mistakes

Not generating update event after changing PSC and ARR.

Using wrong multiplier for ARR.

Forgetting to clear status register before starting timer.

Prescaler divides 16MHz to 1kHz (16000), ARR counts ms ticks, EGR_UG generates update event.