GPIO port-wide operations in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set all pins of GPIO port A as output.

Embedded C

GPIOA->MODER = [1];

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A0x55555555

B0xAAAAAAAA

C0x00000000

D0xFFFFFFFF

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0xFFFFFFFF sets all bits to '11' which is analog mode.

Using 0x00000000 sets all pins as input.

Each pin requires 2 bits in MODER. Setting all pins as output means setting each 2-bit pair to '01', which corresponds to 0x55555555.

2fill in blank

medium

Complete the code to write a high level to all pins of GPIO port B.

Embedded C

GPIOB->ODR = [1];

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A0xAAAAAAAA

B0xFFFFFFFF

C0x00000000

D0x55555555

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x00000000 sets all pins low.

Using 0xAAAAAAAA sets alternating pins high and low.

Writing 0xFFFFFFFF sets all output pins to high (logic 1).

3fill in blank

hard

Fix the error in the code to toggle all pins of GPIO port C.

Embedded C

GPIOC->ODR = GPIOC->ODR [1] 0xFFFFFFFF;

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A<<

B|

C&

D^

Attempts:

3 left

💡 Hint

Common Mistakes

Using '&' clears bits.

Using '|' sets bits but does not toggle.

Using '<<' is a shift operation, not toggle.

The XOR operator '^' toggles bits. XOR with 0xFFFFFFFF flips all bits in ODR.

4fill in blank

hard

Fill both blanks to configure GPIO port D pins as input with pull-up resistors enabled.

Embedded C

GPIOD->MODER = [1];
GPIOD->PUPDR = [2];

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

A0x00000000

B0x55555555

C0xAAAAAAAA

D0xFFFFFFFF

Attempts:

3 left

💡 Hint

Common Mistakes

Setting MODER to 0x55555555 configures pins as output, not input.

Setting PUPDR to 0xAAAAAAAA enables pull-down resistors, not pull-up.

Setting MODER to 0x00000000 configures all pins as input (00). Setting PUPDR to 0x55555555 enables pull-up resistors (01 for each pin).

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps each GPIO pin number to its output state if the pin number is greater than 4.

Embedded C

pin_states = [1]: GPIOE->ODR & (1 << [2]) != 0 for [3] in range(8) if [3] > 4

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

Apin

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causes syntax errors.

Not shifting 1 by the pin number causes wrong bit checking.

The comprehension maps each pin number (pin) to its output state by checking the bit in ODR shifted by pin. The variable iterates as 'pin' in range(8) and filters pins greater than 4.