/* | |
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*************************************************************************** | |
* * | |
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation * | |
* * | |
* This is a concise, step by step, 'hands on' guide that describes both * | |
* general multitasking concepts and FreeRTOS specifics. It presents and * | |
* explains numerous examples that are written using the FreeRTOS API. * | |
* Full source code for all the examples is provided in an accompanying * | |
* .zip file. * | |
* * | |
*************************************************************************** | |
1 tab == 4 spaces! | |
Please ensure to read the configuration and relevant port sections of the | |
online documentation. | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
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*/ | |
/** | |
* This is a very simple queue test. See the BlockQ. c documentation for a more | |
* comprehensive version. | |
* | |
* 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. | |
* | |
* \page PollQC pollQ.c | |
* \ingroup DemoFiles | |
* <HR> | |
*/ | |
/* | |
Changes from V2.0.0 | |
+ Delay periods are now specified using variables and constants of | |
portTickType rather than unsigned portLONG. | |
*/ | |
#include <stdlib.h> | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "queue.h" | |
#include "print.h" | |
/* Demo program include files. */ | |
#include "PollQ.h" | |
#define pollqSTACK_SIZE ( ( unsigned portSHORT ) configMINIMAL_STACK_SIZE ) | |
/* The task that posts the incrementing number onto the queue. */ | |
static void vPolledQueueProducer( void *pvParameters ); | |
/* The task that empties the queue. */ | |
static void vPolledQueueConsumer( void *pvParameters ); | |
/* Variables that are used to check that the tasks are still running with no errors. */ | |
static volatile portSHORT sPollingConsumerCount = 0, sPollingProducerCount = 0; | |
/*-----------------------------------------------------------*/ | |
void vStartPolledQueueTasks( unsigned portBASE_TYPE uxPriority ) | |
{ | |
static xQueueHandle xPolledQueue; | |
const unsigned portBASE_TYPE uxQueueSize = 10; | |
/* Create the queue used by the producer and consumer. */ | |
xPolledQueue = xQueueCreate( uxQueueSize, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) ); | |
/* Spawn the producer and consumer. */ | |
xTaskCreate( vPolledQueueConsumer, "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, NULL ); | |
xTaskCreate( vPolledQueueProducer, "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, NULL ); | |
} | |
/*-----------------------------------------------------------*/ | |
static void vPolledQueueProducer( void *pvParameters ) | |
{ | |
unsigned portSHORT usValue = 0, usLoop; | |
xQueueHandle *pxQueue; | |
const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS; | |
const unsigned portSHORT usNumToProduce = 3; | |
const portCHAR * const pcTaskStartMsg = "Polled queue producer started.\r\n"; | |
const portCHAR * const pcTaskErrorMsg = "Could not post on polled queue.\r\n"; | |
portSHORT sError = pdFALSE; | |
/* Queue a message for printing to say the task has started. */ | |
vPrintDisplayMessage( &pcTaskStartMsg ); | |
/* The queue being used is passed in as the parameter. */ | |
pxQueue = ( xQueueHandle * ) pvParameters; | |
for( ;; ) | |
{ | |
for( usLoop = 0; usLoop < usNumToProduce; ++usLoop ) | |
{ | |
/* Send an incrementing number on the queue without blocking. */ | |
if( xQueueSendToBack( *pxQueue, ( void * ) &usValue, ( portTickType ) 0 ) != pdPASS ) | |
{ | |
/* We should never find the queue full - this is an error. */ | |
vPrintDisplayMessage( &pcTaskErrorMsg ); | |
sError = pdTRUE; | |
} | |
else | |
{ | |
if( sError == pdFALSE ) | |
{ | |
/* If an error has ever been recorded we stop incrementing the | |
check variable. */ | |
++sPollingProducerCount; | |
} | |
/* 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( xDelay ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void vPolledQueueConsumer( void *pvParameters ) | |
{ | |
unsigned portSHORT usData, usExpectedValue = 0; | |
xQueueHandle *pxQueue; | |
const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS; | |
const portCHAR * const pcTaskStartMsg = "Polled queue consumer started.\r\n"; | |
const portCHAR * const pcTaskErrorMsg = "Incorrect value received on polled queue.\r\n"; | |
portSHORT sError = pdFALSE; | |
/* Queue a message for printing to say the task has started. */ | |
vPrintDisplayMessage( &pcTaskStartMsg ); | |
/* The queue being used is passed in as the parameter. */ | |
pxQueue = ( xQueueHandle * ) pvParameters; | |
for( ;; ) | |
{ | |
/* Loop until the queue is empty. */ | |
while( uxQueueMessagesWaiting( *pxQueue ) ) | |
{ | |
if( xQueueReceive( *pxQueue, &usData, ( portTickType ) 0 ) == pdPASS ) | |
{ | |
if( usData != usExpectedValue ) | |
{ | |
/* This is not what we expected to receive so an error has | |
occurred. */ | |
vPrintDisplayMessage( &pcTaskErrorMsg ); | |
sError = pdTRUE; | |
/* Catch-up to the value we received so our next expected value | |
should again be correct. */ | |
usExpectedValue = usData; | |
} | |
else | |
{ | |
if( sError == pdFALSE ) | |
{ | |
/* Only increment the check variable if no errors have | |
occurred. */ | |
++sPollingConsumerCount; | |
} | |
} | |
++usExpectedValue; | |
} | |
} | |
/* Now the queue is empty we block, allowing the producer to place more | |
items in the queue. */ | |
vTaskDelay( xDelay ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
/* This is called to check that all the created tasks are still running with no errors. */ | |
portBASE_TYPE xArePollingQueuesStillRunning( void ) | |
{ | |
static portSHORT sLastPollingConsumerCount = 0, sLastPollingProducerCount = 0; | |
portBASE_TYPE xReturn; | |
if( ( sLastPollingConsumerCount == sPollingConsumerCount ) || | |
( sLastPollingProducerCount == sPollingProducerCount ) | |
) | |
{ | |
xReturn = pdFALSE; | |
} | |
else | |
{ | |
xReturn = pdTRUE; | |
} | |
sLastPollingConsumerCount = sPollingConsumerCount; | |
sLastPollingProducerCount = sPollingProducerCount; | |
return xReturn; | |
} |