480 lines
16 KiB
C
480 lines
16 KiB
C
/*
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* FreeRTOS Kernel V10.2.1
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*
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* The first test creates three tasks - two counter tasks (one continuous count
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* and one limited count) and one controller. A "count" variable is shared
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* between all three tasks. The two counter tasks should never be in a "ready"
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* state at the same time. The controller task runs at the same priority as
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* the continuous count task, and at a lower priority than the limited count
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* task.
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*
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* One counter task loops indefinitely, incrementing the shared count variable
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* on each iteration. To ensure it has exclusive access to the variable it
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* raises its priority above that of the controller task before each
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* increment, lowering it again to its original priority before starting the
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* next iteration.
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*
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* The other counter task increments the shared count variable on each
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* iteration of its loop until the count has reached a limit of 0xff - at
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* which point it suspends itself. It will not start a new loop until the
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* controller task has made it "ready" again by calling vTaskResume().
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* This second counter task operates at a higher priority than controller
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* task so does not need to worry about mutual exclusion of the counter
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* variable.
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*
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* The controller task is in two sections. The first section controls and
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* monitors the continuous count task. When this section is operational the
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* limited count task is suspended. Likewise, the second section controls
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* and monitors the limited count task. When this section is operational the
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* continuous count task is suspended.
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*
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* In the first section the controller task first takes a copy of the shared
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* count variable. To ensure mutual exclusion on the count variable it
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* suspends the continuous count task, resuming it again when the copy has been
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* taken. The controller task then sleeps for a fixed period - during which
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* the continuous count task will execute and increment the shared variable.
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* When the controller task wakes it checks that the continuous count task
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* has executed by comparing the copy of the shared variable with its current
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* value. This time, to ensure mutual exclusion, the scheduler itself is
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* suspended with a call to vTaskSuspendAll (). This is for demonstration
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* purposes only and is not a recommended technique due to its inefficiency.
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*
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* After a fixed number of iterations the controller task suspends the
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* continuous count task, and moves on to its second section.
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*
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* At the start of the second section the shared variable is cleared to zero.
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* The limited count task is then woken from its suspension by a call to
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* vTaskResume (). As this counter task operates at a higher priority than
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* the controller task the controller task should not run again until the
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* shared variable has been counted up to the limited value causing the counter
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* task to suspend itself. The next line after vTaskResume () is therefore
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* a check on the shared variable to ensure everything is as expected.
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*
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*
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* The second test consists of a couple of very simple tasks that post onto a
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* queue while the scheduler is suspended. This test was added to test parts
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* of the scheduler not exercised by the first test.
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*
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*/
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#include <stdlib.h>
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "semphr.h"
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/* Demo app include files. */
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#include "dynamic.h"
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/* Function that implements the "limited count" task as described above. */
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static portTASK_FUNCTION_PROTO( vLimitedIncrementTask, pvParameters );
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/* Function that implements the "continuous count" task as described above. */
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static portTASK_FUNCTION_PROTO( vContinuousIncrementTask, pvParameters );
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/* Function that implements the controller task as described above. */
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static portTASK_FUNCTION_PROTO( vCounterControlTask, pvParameters );
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static portTASK_FUNCTION_PROTO( vQueueReceiveWhenSuspendedTask, pvParameters );
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static portTASK_FUNCTION_PROTO( vQueueSendWhenSuspendedTask, pvParameters );
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/* Demo task specific constants. */
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#ifndef priSUSPENDED_RX_TASK_STACK_SIZE
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#define priSUSPENDED_RX_TASK_STACK_SIZE ( configMINIMAL_STACK_SIZE )
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#endif
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#define priSTACK_SIZE ( configMINIMAL_STACK_SIZE )
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#define priSLEEP_TIME pdMS_TO_TICKS( 128 )
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#define priLOOPS ( 5 )
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#define priMAX_COUNT ( ( uint32_t ) 0xff )
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#define priNO_BLOCK ( ( TickType_t ) 0 )
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#define priSUSPENDED_QUEUE_LENGTH ( 1 )
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/*-----------------------------------------------------------*/
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/* Handles to the two counter tasks. These could be passed in as parameters
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to the controller task to prevent them having to be file scope. */
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static TaskHandle_t xContinuousIncrementHandle, xLimitedIncrementHandle;
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/* The shared counter variable. This is passed in as a parameter to the two
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counter variables for demonstration purposes. */
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static uint32_t ulCounter;
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/* Variables used to check that the tasks are still operating without error.
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Each complete iteration of the controller task increments this variable
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provided no errors have been found. The variable maintaining the same value
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is therefore indication of an error. */
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static volatile uint16_t usCheckVariable = ( uint16_t ) 0;
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static volatile BaseType_t xSuspendedQueueSendError = pdFALSE;
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static volatile BaseType_t xSuspendedQueueReceiveError = pdFALSE;
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/* Queue used by the second test. */
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QueueHandle_t xSuspendedTestQueue;
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/* The value the queue receive task expects to receive next. This is file
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scope so xAreDynamicPriorityTasksStillRunning() can ensure it is still
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incrementing. */
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static uint32_t ulExpectedValue = ( uint32_t ) 0;
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/*-----------------------------------------------------------*/
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/*
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* Start the three tasks as described at the top of the file.
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* Note that the limited count task is given a higher priority.
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*/
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void vStartDynamicPriorityTasks( void )
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{
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xSuspendedTestQueue = xQueueCreate( priSUSPENDED_QUEUE_LENGTH, sizeof( uint32_t ) );
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if( xSuspendedTestQueue != NULL )
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{
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/* vQueueAddToRegistry() adds the queue to the queue registry, if one is
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in use. The queue registry is provided as a means for kernel aware
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debuggers to locate queues and has no purpose if a kernel aware debugger
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is not being used. The call to vQueueAddToRegistry() will be removed
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by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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defined to be less than 1. */
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vQueueAddToRegistry( xSuspendedTestQueue, "Suspended_Test_Queue" );
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xTaskCreate( vContinuousIncrementTask, "CNT_INC", priSTACK_SIZE, ( void * ) &ulCounter, tskIDLE_PRIORITY, &xContinuousIncrementHandle );
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xTaskCreate( vLimitedIncrementTask, "LIM_INC", priSTACK_SIZE, ( void * ) &ulCounter, tskIDLE_PRIORITY + 1, &xLimitedIncrementHandle );
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xTaskCreate( vCounterControlTask, "C_CTRL", priSUSPENDED_RX_TASK_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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xTaskCreate( vQueueSendWhenSuspendedTask, "SUSP_TX", priSTACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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xTaskCreate( vQueueReceiveWhenSuspendedTask, "SUSP_RX", priSUSPENDED_RX_TASK_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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}
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}
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/*-----------------------------------------------------------*/
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/*
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* Just loops around incrementing the shared variable until the limit has been
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* reached. Once the limit has been reached it suspends itself.
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*/
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static portTASK_FUNCTION( vLimitedIncrementTask, pvParameters )
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{
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volatile uint32_t *pulCounter;
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/* Take a pointer to the shared variable from the parameters passed into
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the task. */
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pulCounter = ( volatile uint32_t * ) pvParameters;
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/* This will run before the control task, so the first thing it does is
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suspend - the control task will resume it when ready. */
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vTaskSuspend( NULL );
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for( ;; )
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{
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/* Just count up to a value then suspend. */
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( *pulCounter )++;
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if( *pulCounter >= priMAX_COUNT )
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{
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vTaskSuspend( NULL );
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}
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}
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}
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/*-----------------------------------------------------------*/
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/*
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* Just keep counting the shared variable up. The control task will suspend
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* this task when it wants.
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*/
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static portTASK_FUNCTION( vContinuousIncrementTask, pvParameters )
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{
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volatile uint32_t *pulCounter;
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UBaseType_t uxOurPriority;
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/* Take a pointer to the shared variable from the parameters passed into
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the task. */
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pulCounter = ( volatile uint32_t * ) pvParameters;
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/* Query our priority so we can raise it when exclusive access to the
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shared variable is required. */
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uxOurPriority = uxTaskPriorityGet( NULL );
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for( ;; )
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{
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/* Raise the priority above the controller task to ensure a context
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switch does not occur while the variable is being accessed. */
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vTaskPrioritySet( NULL, uxOurPriority + 1 );
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{
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configASSERT( ( uxTaskPriorityGet( NULL ) == ( uxOurPriority + 1 ) ) );
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( *pulCounter )++;
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}
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vTaskPrioritySet( NULL, uxOurPriority );
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#if( configUSE_PREEMPTION == 0 )
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taskYIELD();
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#endif
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configASSERT( ( uxTaskPriorityGet( NULL ) == uxOurPriority ) );
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}
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}
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/*-----------------------------------------------------------*/
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/*
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* Controller task as described above.
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*/
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static portTASK_FUNCTION( vCounterControlTask, pvParameters )
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{
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uint32_t ulLastCounter;
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short sLoops;
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short sError = pdFALSE;
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/* Just to stop warning messages. */
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( void ) pvParameters;
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for( ;; )
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{
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/* Start with the counter at zero. */
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ulCounter = ( uint32_t ) 0;
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/* First section : */
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/* Check the continuous count task is running. */
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for( sLoops = 0; sLoops < priLOOPS; sLoops++ )
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{
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/* Suspend the continuous count task so we can take a mirror of the
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shared variable without risk of corruption. This is not really
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needed as the other task raises its priority above this task's
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priority. */
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vTaskSuspend( xContinuousIncrementHandle );
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{
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#if( INCLUDE_eTaskGetState == 1 )
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{
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configASSERT( eTaskGetState( xContinuousIncrementHandle ) == eSuspended );
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}
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#endif /* INCLUDE_eTaskGetState */
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ulLastCounter = ulCounter;
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}
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vTaskResume( xContinuousIncrementHandle );
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#if( configUSE_PREEMPTION == 0 )
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taskYIELD();
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#endif
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#if( INCLUDE_eTaskGetState == 1 )
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{
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configASSERT( eTaskGetState( xContinuousIncrementHandle ) == eReady );
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}
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#endif /* INCLUDE_eTaskGetState */
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/* Now delay to ensure the other task has processor time. */
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vTaskDelay( priSLEEP_TIME );
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/* Check the shared variable again. This time to ensure mutual
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exclusion the whole scheduler will be locked. This is just for
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demo purposes! */
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vTaskSuspendAll();
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{
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if( ulLastCounter == ulCounter )
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{
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/* The shared variable has not changed. There is a problem
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with the continuous count task so flag an error. */
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sError = pdTRUE;
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}
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}
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xTaskResumeAll();
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}
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/* Second section: */
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/* Suspend the continuous counter task so it stops accessing the shared
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variable. */
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vTaskSuspend( xContinuousIncrementHandle );
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/* Reset the variable. */
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ulCounter = ( uint32_t ) 0;
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#if( INCLUDE_eTaskGetState == 1 )
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{
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configASSERT( eTaskGetState( xLimitedIncrementHandle ) == eSuspended );
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}
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#endif /* INCLUDE_eTaskGetState */
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/* Resume the limited count task which has a higher priority than us.
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We should therefore not return from this call until the limited count
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task has suspended itself with a known value in the counter variable. */
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vTaskResume( xLimitedIncrementHandle );
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#if( configUSE_PREEMPTION == 0 )
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taskYIELD();
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#endif
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/* This task should not run again until xLimitedIncrementHandle has
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suspended itself. */
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#if( INCLUDE_eTaskGetState == 1 )
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{
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configASSERT( eTaskGetState( xLimitedIncrementHandle ) == eSuspended );
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}
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#endif /* INCLUDE_eTaskGetState */
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/* Does the counter variable have the expected value? */
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if( ulCounter != priMAX_COUNT )
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{
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sError = pdTRUE;
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}
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if( sError == pdFALSE )
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{
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/* If no errors have occurred then increment the check variable. */
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portENTER_CRITICAL();
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usCheckVariable++;
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portEXIT_CRITICAL();
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}
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/* Resume the continuous count task and do it all again. */
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vTaskResume( xContinuousIncrementHandle );
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#if( configUSE_PREEMPTION == 0 )
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taskYIELD();
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#endif
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}
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}
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/*-----------------------------------------------------------*/
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static portTASK_FUNCTION( vQueueSendWhenSuspendedTask, pvParameters )
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{
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static uint32_t ulValueToSend = ( uint32_t ) 0;
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/* Just to stop warning messages. */
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( void ) pvParameters;
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for( ;; )
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{
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vTaskSuspendAll();
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{
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/* We must not block while the scheduler is suspended! */
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if( xQueueSend( xSuspendedTestQueue, ( void * ) &ulValueToSend, priNO_BLOCK ) != pdTRUE )
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{
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xSuspendedQueueSendError = pdTRUE;
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}
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}
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xTaskResumeAll();
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vTaskDelay( priSLEEP_TIME );
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++ulValueToSend;
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}
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}
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/*-----------------------------------------------------------*/
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static portTASK_FUNCTION( vQueueReceiveWhenSuspendedTask, pvParameters )
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{
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uint32_t ulReceivedValue;
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BaseType_t xGotValue;
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/* Just to stop warning messages. */
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( void ) pvParameters;
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for( ;; )
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{
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do
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{
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/* Suspending the scheduler here is fairly pointless and
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undesirable for a normal application. It is done here purely
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to test the scheduler. The inner xTaskResumeAll() should
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never return pdTRUE as the scheduler is still locked by the
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outer call. */
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vTaskSuspendAll();
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{
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vTaskSuspendAll();
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{
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xGotValue = xQueueReceive( xSuspendedTestQueue, ( void * ) &ulReceivedValue, priNO_BLOCK );
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}
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if( xTaskResumeAll() != pdFALSE )
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{
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xSuspendedQueueReceiveError = pdTRUE;
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}
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}
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xTaskResumeAll();
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#if configUSE_PREEMPTION == 0
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{
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taskYIELD();
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}
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#endif
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} while( xGotValue == pdFALSE );
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if( ulReceivedValue != ulExpectedValue )
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{
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xSuspendedQueueReceiveError = pdTRUE;
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}
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if( xSuspendedQueueReceiveError != pdTRUE )
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{
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/* Only increment the variable if an error has not occurred. This
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allows xAreDynamicPriorityTasksStillRunning() to check for stalled
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tasks as well as explicit errors. */
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++ulExpectedValue;
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}
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}
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}
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/*-----------------------------------------------------------*/
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/* Called to check that all the created tasks are still running without error. */
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BaseType_t xAreDynamicPriorityTasksStillRunning( void )
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{
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/* Keep a history of the check variables so we know if it has been incremented
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since the last call. */
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static uint16_t usLastTaskCheck = ( uint16_t ) 0;
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static uint32_t ulLastExpectedValue = ( uint32_t ) 0U;
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BaseType_t xReturn = pdTRUE;
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/* Check the tasks are still running by ensuring the check variable
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is still incrementing. */
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if( usCheckVariable == usLastTaskCheck )
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{
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/* The check has not incremented so an error exists. */
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xReturn = pdFALSE;
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}
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if( ulExpectedValue == ulLastExpectedValue )
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{
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/* The value being received by the queue receive task has not
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incremented so an error exists. */
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xReturn = pdFALSE;
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}
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if( xSuspendedQueueSendError == pdTRUE )
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{
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xReturn = pdFALSE;
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}
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if( xSuspendedQueueReceiveError == pdTRUE )
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{
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xReturn = pdFALSE;
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}
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usLastTaskCheck = usCheckVariable;
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ulLastExpectedValue = ulExpectedValue;
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return xReturn;
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}
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