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*/ | |
/* | |
* This version of PollQ. c is for use on systems that have limited stack | |
* space and no display facilities. The complete version can be found in | |
* the Demo/Common/Full directory. | |
* | |
* Creates two tasks that communicate over a single queue. One task acts as a | |
* producer, the other a consumer. | |
* | |
* The producer loops for three iteration, posting an incrementing number onto the | |
* queue each cycle. It then delays for a fixed period before doing exactly the | |
* same again. | |
* | |
* The consumer loops emptying the queue. Each item removed from the queue is | |
* checked to ensure it contains the expected value. When the queue is empty it | |
* blocks for a fixed period, then does the same again. | |
* | |
* All queue access is performed without blocking. The consumer completely empties | |
* the queue each time it runs so the producer should never find the queue full. | |
* | |
* An error is flagged if the consumer obtains an unexpected value or the producer | |
* find the queue is full. | |
*/ | |
/* | |
Changes from V2.0.0 | |
+ Delay periods are now specified using variables and constants of | |
TickType_t rather than unsigned long. | |
*/ | |
#include <stdlib.h> | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "queue.h" | |
/* Demo program include files. */ | |
#include "PollQ.h" | |
#define pollqSTACK_SIZE configMINIMAL_STACK_SIZE | |
#define pollqQUEUE_SIZE ( 10 ) | |
#define pollqPRODUCER_DELAY ( ( TickType_t ) 200 / portTICK_PERIOD_MS ) | |
#define pollqCONSUMER_DELAY ( pollqPRODUCER_DELAY - ( TickType_t ) ( 20 / portTICK_PERIOD_MS ) ) | |
#define pollqNO_DELAY ( ( TickType_t ) 0 ) | |
#define pollqVALUES_TO_PRODUCE ( ( signed portBASE_TYPE ) 3 ) | |
#define pollqINITIAL_VALUE ( ( signed portBASE_TYPE ) 0 ) | |
/* The task that posts the incrementing number onto the queue. */ | |
static portTASK_FUNCTION_PROTO( vPolledQueueProducer, pvParameters ); | |
/* The task that empties the queue. */ | |
static portTASK_FUNCTION_PROTO( vPolledQueueConsumer, pvParameters ); | |
/* Variables that are used to check that the tasks are still running with no | |
errors. */ | |
static volatile signed portBASE_TYPE xPollingConsumerCount = pollqINITIAL_VALUE, xPollingProducerCount = pollqINITIAL_VALUE; | |
/*-----------------------------------------------------------*/ | |
void vStartPolledQueueTasks( unsigned portBASE_TYPE uxPriority ) | |
{ | |
static QueueHandle_t xPolledQueue; | |
/* Create the queue used by the producer and consumer. */ | |
xPolledQueue = xQueueCreate( pollqQUEUE_SIZE, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) ); | |
/* vQueueAddToRegistry() adds the queue to the queue registry, if one is | |
in use. The queue registry is provided as a means for kernel aware | |
debuggers to locate queues and has no purpose if a kernel aware debugger | |
is not being used. The call to vQueueAddToRegistry() will be removed | |
by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is | |
defined to be less than 1. */ | |
vQueueAddToRegistry( xPolledQueue, "Poll_Test_Queue" ); | |
/* Spawn the producer and consumer. */ | |
xTaskCreate( vPolledQueueConsumer, "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( TaskHandle_t * ) NULL ); | |
xTaskCreate( vPolledQueueProducer, "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( TaskHandle_t * ) NULL ); | |
} | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vPolledQueueProducer, pvParameters ) | |
{ | |
unsigned short usValue = ( unsigned short ) 0; | |
signed portBASE_TYPE xError = pdFALSE, xLoop; | |
for( ;; ) | |
{ | |
for( xLoop = 0; xLoop < pollqVALUES_TO_PRODUCE; xLoop++ ) | |
{ | |
/* Send an incrementing number on the queue without blocking. */ | |
if( xQueueSend( *( ( QueueHandle_t * ) pvParameters ), ( void * ) &usValue, pollqNO_DELAY ) != pdPASS ) | |
{ | |
/* We should never find the queue full so if we get here there | |
has been an error. */ | |
xError = pdTRUE; | |
} | |
else | |
{ | |
if( xError == pdFALSE ) | |
{ | |
/* If an error has ever been recorded we stop incrementing the | |
check variable. */ | |
portENTER_CRITICAL(); | |
xPollingProducerCount++; | |
portEXIT_CRITICAL(); | |
} | |
/* Update the value we are going to post next time around. */ | |
usValue++; | |
} | |
} | |
/* Wait before we start posting again to ensure the consumer runs and | |
empties the queue. */ | |
vTaskDelay( pollqPRODUCER_DELAY ); | |
} | |
} /*lint !e818 Function prototype must conform to API. */ | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vPolledQueueConsumer, pvParameters ) | |
{ | |
unsigned short usData, usExpectedValue = ( unsigned short ) 0; | |
signed portBASE_TYPE xError = pdFALSE; | |
for( ;; ) | |
{ | |
/* Loop until the queue is empty. */ | |
while( uxQueueMessagesWaiting( *( ( QueueHandle_t * ) pvParameters ) ) ) | |
{ | |
if( xQueueReceive( *( ( QueueHandle_t * ) pvParameters ), &usData, pollqNO_DELAY ) == pdPASS ) | |
{ | |
if( usData != usExpectedValue ) | |
{ | |
/* This is not what we expected to receive so an error has | |
occurred. */ | |
xError = pdTRUE; | |
/* Catch-up to the value we received so our next expected | |
value should again be correct. */ | |
usExpectedValue = usData; | |
} | |
else | |
{ | |
if( xError == pdFALSE ) | |
{ | |
/* Only increment the check variable if no errors have | |
occurred. */ | |
portENTER_CRITICAL(); | |
xPollingConsumerCount++; | |
portEXIT_CRITICAL(); | |
} | |
} | |
/* Next time round we would expect the number to be one higher. */ | |
usExpectedValue++; | |
} | |
} | |
/* Now the queue is empty we block, allowing the producer to place more | |
items in the queue. */ | |
vTaskDelay( pollqCONSUMER_DELAY ); | |
} | |
} /*lint !e818 Function prototype must conform to API. */ | |
/*-----------------------------------------------------------*/ | |
/* This is called to check that all the created tasks are still running with no errors. */ | |
portBASE_TYPE xArePollingQueuesStillRunning( void ) | |
{ | |
portBASE_TYPE xReturn; | |
/* Check both the consumer and producer poll count to check they have both | |
been changed since out last trip round. We do not need a critical section | |
around the check variables as this is called from a higher priority than | |
the other tasks that access the same variables. */ | |
if( ( xPollingConsumerCount == pollqINITIAL_VALUE ) || | |
( xPollingProducerCount == pollqINITIAL_VALUE ) | |
) | |
{ | |
xReturn = pdFALSE; | |
} | |
else | |
{ | |
xReturn = pdTRUE; | |
} | |
/* Set the check variables back down so we know if they have been | |
incremented the next time around. */ | |
xPollingConsumerCount = pollqINITIAL_VALUE; | |
xPollingProducerCount = pollqINITIAL_VALUE; | |
return xReturn; | |
} |