Pull-up and pull-down resistor configuration in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable the pull-up resistor on the input pin.

Embedded C

GPIO_PORT->PULLUP_EN = [1];

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

A0x10

B0xFF

C0x00

D0x01

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x00 disables the resistor.

Using 0xFF enables all pins, not just the input pin.

The pull-up resistor is enabled by setting the correct bit mask. Here, 0x10 corresponds to the input pin.

2fill in blank

medium

Complete the code to configure the pin as input with pull-down resistor enabled.

Embedded C

GPIO_PORT->DIR &= ~[1];  // Set pin as input
GPIO_PORT->PULLDOWN_EN = [1];

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

A0x04

B0x08

C0x02

D0x01

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the pin as output by mistake.

Using different masks for DIR and PULLDOWN_EN.

The pin mask 0x04 is used to clear the direction bit (input) and enable the pull-down resistor on that pin.

3fill in blank

hard

Fix the error in the code to correctly enable pull-up resistor on pin 5.

Embedded C

GPIO_PORT->PULLUP_EN |= [1];  // Enable pull-up on pin 5

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

A0x10

B0x40

C0x08

D0x20

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x10 which is bit 4.

Using 0x40 which is bit 6.

Pin 5 corresponds to bit 5, which is 0x20 in hexadecimal.

4fill in blank

hard

Fill both blanks to configure pin 3 as input.

Embedded C

GPIO_PORT->DIR [1]= [2]0x08;  // Configure pin 3 as input

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

A&

B|

C~

D^

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR (|) instead of AND (&).

Not inverting the pin mask (~).

To set pin 3 as input, clear bit 3 using bitwise AND with the complement (~) of the pin mask.

5fill in blank

hard

Fill all three blanks to create a dictionary mapping pin numbers to their pull-up status (1 for enabled, 0 for disabled) for pins 1, 2, and 3.

Embedded C

int pullup_status[] = { [1], [2], [3] };

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

AGPIO_PORT->PULLUP_EN & 0x02 ? 1 : 0

BGPIO_PORT->PULLUP_EN & 0x04 ? 1 : 0

CGPIO_PORT->PULLUP_EN & 0x08 ? 1 : 0

DGPIO_PORT->PULLUP_EN & 0x10 ? 1 : 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong bit masks for pins.

Not using ternary operator for boolean to int conversion.

Each expression checks if the pull-up resistor is enabled on pins 1, 2, and 3 respectively by masking the correct bit.