Graceful shutdown sequence in FreeRTOS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to notify the shutdown event.

FreeRTOS

xEventGroupSetBits(shutdownEventGroup, [1]);

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ASHUTDOWN_BIT

BSTART_BIT

CERROR_BIT

DRUNNING_BIT

Attempts:

3 left

💡 Hint

Common Mistakes

Using START_BIT instead of SHUTDOWN_BIT.

Forgetting to set any event bit.

Using ERROR_BIT which signals errors, not shutdown.

The shutdown event is signaled by setting the SHUTDOWN_BIT in the event group.

2fill in blank

medium

Complete the code to wait for the shutdown event.

FreeRTOS

xEventGroupWaitBits(shutdownEventGroup, [1], pdTRUE, pdFALSE, portMAX_DELAY);

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

ASHUTDOWN_BIT

BERROR_BIT

CSTART_BIT

DRUNNING_BIT

Attempts:

3 left

💡 Hint

Common Mistakes

Waiting on START_BIT which is unrelated to shutdown.

Using pdFALSE for clearOnExit incorrectly.

Not using portMAX_DELAY to wait indefinitely.

Waiting for SHUTDOWN_BIT ensures the task blocks until shutdown is requested.

3fill in blank

hard

Fix the error in the shutdown task loop condition.

FreeRTOS

while (![1](shutdownEventGroup, SHUTDOWN_BIT, pdTRUE, pdFALSE, 0)) {
    vTaskDelay(pdMS_TO_TICKS(100));
}

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AxEventGroupSync

BxEventGroupWaitBits

CxEventGroupSetBits

DxEventGroupClearBits

Attempts:

3 left

💡 Hint

Common Mistakes

Using xEventGroupSetBits which sets bits instead of waiting.

Using xEventGroupClearBits which clears bits but does not wait.

Using xEventGroupSync which is for synchronization, not bit checking.

xEventGroupWaitBits is used to check event bits with timeout; others do not return bit status.

4fill in blank

hard

Fill both blanks to correctly stop peripherals and delete the task.

FreeRTOS

stopPeripheral([1]);
vTaskDelete([2]);

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AperipheralHandle

BNULL

CtaskHandle

DperipheralID

Attempts:

3 left

💡 Hint

Common Mistakes

Passing taskHandle to stopPeripheral instead of peripheral ID.

Passing NULL to stopPeripheral which expects an ID.

Passing taskHandle to vTaskDelete instead of NULL.

stopPeripheral needs the peripheral ID; vTaskDelete(NULL) deletes the current task.

5fill in blank

hard

Fill all three blanks to create a graceful shutdown sequence with notification, wait, and cleanup.

FreeRTOS

xEventGroupSetBits(shutdownEventGroup, [1]);

xEventGroupWaitBits(shutdownEventGroup, [2], pdTRUE, pdFALSE, portMAX_DELAY);

cleanupResources([3]);

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ASHUTDOWN_BIT

CresourceHandle

DtaskHandle

Attempts:

3 left

💡 Hint

Common Mistakes

Using different bits for set and wait causing deadlock.

Passing taskHandle instead of resourceHandle to cleanupResources.

Not waiting for shutdown event before cleanup.

Set and wait on SHUTDOWN_BIT to coordinate shutdown; cleanupResources needs the resource handle.