Event-driven architecture in FreeRTOS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an event group in FreeRTOS.

FreeRTOS

EventGroupHandle_t [1] = xEventGroupCreate();

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AeventGroup

BxQueue

CtaskHandle

DtimerID

Attempts:

3 left

💡 Hint

Common Mistakes

Using a queue or task handle variable name instead of an event group handle.

Not assigning the return value of xEventGroupCreate() to a variable.

The function xEventGroupCreate() returns a handle to an event group, which we store in eventGroup.

2fill in blank

medium

Complete the code to wait for an event bit to be set in the event group.

FreeRTOS

EventBits_t bits = xEventGroupWaitBits(eventGroup, [1], pdTRUE, pdFALSE, portMAX_DELAY);

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A0xFF

B0x00

C0x10

D0x01

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0x00 which waits for no bits.

Using 0xFF which waits for all bits set.

The bit mask 0x01 waits for the first event bit to be set.

3fill in blank

hard

Fix the error in the code to set an event bit in the event group.

FreeRTOS

xEventGroup[1]Bits(eventGroup, 0x01);

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ACreate

BClear

CSet

DWait

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ClearBits' which clears bits instead of setting.

Using 'WaitBits' which waits for bits instead of setting.

The function to set bits in an event group is xEventGroupSetBits().

4fill in blank

hard

Fill both blanks to create an event group and check if a specific bit is set.

FreeRTOS

EventGroupHandle_t [1] = xEventGroupCreate();
if (xEventGroupGetBits([2]) & 0x02) {
    // Event bit 2 is set
}

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AmyEventGroup

BeventQueue

DtaskHandle

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for creation and checking.

Using a queue or task handle instead of an event group handle.

We create the event group with myEventGroup and check its bits using the same handle.

5fill in blank

hard

Fill all three blanks to set multiple event bits and then clear one bit.

FreeRTOS

xEventGroupSetBits([1], 0x03);
xEventGroupClearBits([2], [3]);

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

AeventGroupHandle

C0x01

D0x02

Attempts:

3 left

💡 Hint

Common Mistakes

Using different handles for set and clear functions.

Clearing the wrong bit mask.

We set bits 0 and 1 with 0x03, then clear bit 0 with 0x01 on the same event group handle.