NVIC (Nested Vectored Interrupt Controller) in ARM Architecture - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable an interrupt in the NVIC.

ARM Architecture

NVIC->ISER[0] = 1 << [1];

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A3

B5

C10

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using the interrupt number directly without shifting.

Using an incorrect interrupt number.

The NVIC interrupt set-enable register (ISER) uses bit positions to enable interrupts. Shifting 1 by the interrupt number enables that interrupt. Here, 3 is the correct interrupt number to enable.

2fill in blank

medium

Complete the code to set the priority of an interrupt in the NVIC.

ARM Architecture

NVIC->IP[[1]] = 0x20;

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A5

B10

C0

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong index that does not match the interrupt number.

Confusing priority value with interrupt number.

The NVIC interrupt priority register (IP) array uses the interrupt number as the index. Setting IP[2] assigns priority to interrupt number 2.

3fill in blank

hard

Fix the error in the code to disable an interrupt in the NVIC.

ARM Architecture

NVIC->[1][0] = 1 << 4;

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AICER

BICPR

CISPR

DISER

Attempts:

3 left

💡 Hint

Common Mistakes

Using ISER instead of ICER to disable interrupts.

Using pending registers instead of enable/disable registers.

To disable an interrupt, the NVIC interrupt clear-enable register (ICER) must be used, not ISER which enables interrupts.

4fill in blank

hard

Fill both blanks to check if interrupt 7 is pending and clear it in the NVIC.

ARM Architecture

if (NVIC->[1][0] & (1 << 7)) {
    NVIC->[2][0] = 1 << 7;
}

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AISPR

BICPR

CISER

DICER

Attempts:

3 left

💡 Hint

Common Mistakes

Using enable/disable registers instead of pending registers.

Confusing set-pending with clear-pending registers.

ISPR is the interrupt set-pending register used to check if an interrupt is pending. ICPR is the interrupt clear-pending register used to clear the pending status.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps interrupt numbers to their priority if priority is less than 128.

ARM Architecture

{ [1]: NVIC.IP[[2]] for [3] in range(32) if NVIC.IP[[2]] < 128 }

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Ai

Dj

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Using a variable not defined in the comprehension.

Using 'i' as the loop variable and key/index variable is standard. The comprehension maps interrupt number i to its priority if priority is less than 128.