ulTaskNotifyTake() for binary/counting notification in FreeRTOS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to wait for a notification using ulTaskNotifyTake.

FreeRTOS

uint32_t ulNotificationValue = ulTaskNotifyTake(pdTRUE, [1]);

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

AportMAX_DELAY

B0

C1000

DpdFALSE

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 as block time causes no waiting and immediate return.

Using pdFALSE instead of a block time is incorrect.

ulTaskNotifyTake waits indefinitely for a notification when the block time is set to portMAX_DELAY.

2fill in blank

medium

Complete the code to clear the notification value on exit.

FreeRTOS

uint32_t ulNotificationValue = ulTaskNotifyTake([1], portMAX_DELAY);

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

A0

BpdFALSE

C1

DpdTRUE

Attempts:

3 left

💡 Hint

Common Mistakes

Using pdFALSE keeps the notification count unchanged.

Using 0 or 1 instead of pdTRUE or pdFALSE can cause confusion.

Setting ulClearCountOnExit to pdTRUE clears the notification value when the function returns.

3fill in blank

hard

Fix the error in the code to correctly receive a counting notification.

FreeRTOS

uint32_t ulNotificationValue = ulTaskNotifyTake(pdTRUE, [1]);

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

A0

B-1

CportMAX_DELAY

DpdFALSE

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 causes no wait and immediate return.

Using negative values is invalid.

The block time must be a valid tick count or portMAX_DELAY to wait properly. Using 0 causes immediate return.

4fill in blank

hard

Fill both blanks to create a counting notification wait that clears on exit and waits forever.

FreeRTOS

uint32_t ulNotificationValue = ulTaskNotifyTake([1], [2]);

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

ApdTRUE

BpdFALSE

CportMAX_DELAY

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping parameters causes wrong behavior.

Using 0 as block time causes no wait.

Use pdTRUE to clear the count on exit and portMAX_DELAY to wait indefinitely.

5fill in blank

hard

Fill all three blanks to check if a notification was received and print its value.

FreeRTOS

uint32_t ulNotificationValue = ulTaskNotifyTake([1], [2]);
if (ulNotificationValue [3] 0) {
    printf("Notification count: %u\n", ulNotificationValue);
}

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

ApdTRUE

BportMAX_DELAY

C>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using == 0 checks for no notification, not received.

Not clearing count can cause repeated notifications.

Clear count on exit with pdTRUE, wait forever with portMAX_DELAY, and check if notification count is greater than 0.