/* FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd. This file is part of the FreeRTOS distribution. FreeRTOS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (version 2) as published by the Free Software Foundation and modified by the FreeRTOS exception. **NOTE** The exception to the GPL is included to allow you to distribute a combined work that includes FreeRTOS without being obliged to provide the source code for proprietary components outside of the FreeRTOS kernel. Alternative commercial license and support terms are also available upon request. See the licensing section of http://www.FreeRTOS.org for full license details. FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. *************************************************************************** * * * Looking for a quick start? Then check out the FreeRTOS eBook! * * See http://www.FreeRTOS.org/Documentation for details * * * *************************************************************************** 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 contact details. http://www.SafeRTOS.com - A version that is certified for use in safety critical systems. http://www.OpenRTOS.com - Commercial support, development, porting, licensing and training services. */ /* * 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 portTickType rather than unsigned portLONG. */ #include /* 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 ( ( portTickType ) 200 / portTICK_RATE_MS ) #define pollqCONSUMER_DELAY ( pollqPRODUCER_DELAY - ( portTickType ) ( 20 / portTICK_RATE_MS ) ) #define pollqNO_DELAY ( ( portTickType ) 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 xQueueHandle xPolledQueue; /* Create the queue used by the producer and consumer. */ xPolledQueue = xQueueCreate( pollqQUEUE_SIZE, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) ); /* 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, ( signed portCHAR * ) "Poll_Test_Queue" ); /* Spawn the producer and consumer. */ xTaskCreate( vPolledQueueConsumer, ( signed portCHAR * ) "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL ); xTaskCreate( vPolledQueueProducer, ( signed portCHAR * ) "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL ); } /*-----------------------------------------------------------*/ static portTASK_FUNCTION( vPolledQueueProducer, pvParameters ) { unsigned portSHORT usValue = ( unsigned portSHORT ) 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( *( ( xQueueHandle * ) 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 portSHORT usData, usExpectedValue = ( unsigned portSHORT ) 0; signed portBASE_TYPE xError = pdFALSE; for( ;; ) { /* Loop until the queue is empty. */ while( uxQueueMessagesWaiting( *( ( xQueueHandle * ) pvParameters ) ) ) { if( xQueueReceive( *( ( xQueueHandle * ) 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; }