Why interrupts are needed in Embedded C - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an interrupt service routine (ISR) function.

Embedded C

void [1]() {
    // ISR code here
}

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

AISR_Handler

Bmain

Cloop

Dsetup

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'main' or 'loop' as ISR function name.

The function that handles an interrupt is called an ISR (Interrupt Service Routine). Naming it ISR_Handler is a common practice.

2fill in blank

medium

Complete the code to enable global interrupts in the microcontroller.

Embedded C

sei(); // [1] interrupts

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

Areset

Bdisable

Cignore

Denable

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing enable with disable or reset.

The sei() function enables global interrupts in many embedded C environments.

3fill in blank

hard

Fix the error in the code to correctly declare an ISR for timer overflow.

Embedded C

ISR([1]) {
    // Timer overflow code
}

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

Atimer_interrupt

BTIMER0_OVF_vect

Cmain

Doverflow_handler

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic or incorrect names like 'main' or 'timer_interrupt'.

The correct vector name for Timer0 overflow interrupt is TIMER0_OVF_vect.

4fill in blank

hard

Fill both blanks to create a dictionary that maps interrupt names to their priority levels.

Embedded C

const int interrupt_priority[] = {
    [[1]] = 1,
    [[2]] = 2
};

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

ATIMER0_OVF_vect

BUSART_RX_vect

CADC_vect

DINT0_vect

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid or duplicate interrupt names.

We map TIMER0_OVF_vect to priority 1 and USART_RX_vect to priority 2 as an example.

5fill in blank

hard

Fill all three blanks to complete the code that checks if an interrupt flag is set and clears it.

Embedded C

if ([1] & (1 << [2])) {
    [3] |= (1 << [2]); // Clear flag
}

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

ATIFR

BTOV0

DTIMSK

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong registers or bits to check or clear flags.

The TIFR register holds interrupt flags. TOV0 is the Timer0 overflow flag bit. Clearing the flag is done by writing 1 to the bit in TIFR.