root/webserver/example/freeRTOSexample/EnergyMeters/Common/Minimal/crflash.c

/*
        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.


        ***************************************************************************
        *                                                                         *
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        * See http://www.FreeRTOS.org/Documentation for details                   *
        *                                                                         *
        ***************************************************************************

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        Please ensure to read the configuration and relevant port sections of the
        online documentation.

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*/

/*
 * This demo application file demonstrates the use of queues to pass data
 * between co-routines.
 *
 * N represents the number of 'fixed delay' co-routines that are created and
 * is set during initialisation.
 *
 * N 'fixed delay' co-routines are created that just block for a fixed
 * period then post the number of an LED onto a queue.  Each such co-routine
 * uses a different block period.  A single 'flash' co-routine is also created
 * that blocks on the same queue, waiting for the number of the next LED it
 * should flash.  Upon receiving a number it simply toggle the instructed LED
 * then blocks on the queue once more.  In this manner each LED from LED 0 to
 * LED N-1 is caused to flash at a different rate.
 *
 * The 'fixed delay' co-routines are created with co-routine priority 0.  The
 * flash co-routine is created with co-routine priority 1.  This means that
 * the queue should never contain more than a single item.  This is because
 * posting to the queue will unblock the 'flash' co-routine, and as this has
 * a priority greater than the tasks posting to the queue it is guaranteed to
 * have emptied the queue and blocked once again before the queue can contain
 * any more date.  An error is indicated if an attempt to post data to the
 * queue fails - indicating that the queue is already full.
 *
 */

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "croutine.h"
#include "queue.h"

/* Demo application includes. */
#include "partest.h"
#include "crflash.h"

/* The queue should only need to be of length 1.  See the description at the
top of the file. */
#define crfQUEUE_LENGTH         1

#define crfFIXED_DELAY_PRIORITY         0
#define crfFLASH_PRIORITY                       1

/* Only one flash co-routine is created so the index is not significant. */
#define crfFLASH_INDEX                          0

/* Don't allow more than crfMAX_FLASH_TASKS 'fixed delay' co-routines to be
created. */
#define crfMAX_FLASH_TASKS                      8

/* We don't want to block when posting to the queue. */
#define crfPOSTING_BLOCK_TIME           0

/*
 * The 'fixed delay' co-routine as described at the top of the file.
 */
static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );

/*
 * The 'flash' co-routine as described at the top of the file.
 */
static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );

/* The queue used to pass data between the 'fixed delay' co-routines and the
'flash' co-routine. */
static xQueueHandle xFlashQueue;

/* This will be set to pdFALSE if we detect an error. */
static portBASE_TYPE xCoRoutineFlashStatus = pdPASS;

/*-----------------------------------------------------------*/

/*
 * See the header file for details.
 */
void vStartFlashCoRoutines( unsigned portBASE_TYPE uxNumberToCreate )
{
unsigned portBASE_TYPE uxIndex;

        if( uxNumberToCreate > crfMAX_FLASH_TASKS )
        {
                uxNumberToCreate = crfMAX_FLASH_TASKS;
        }

        /* Create the queue used to pass data between the co-routines. */
        xFlashQueue = xQueueCreate( crfQUEUE_LENGTH, sizeof( unsigned portBASE_TYPE ) );

        if( xFlashQueue )
        {
                /* Create uxNumberToCreate 'fixed delay' co-routines. */
                for( uxIndex = 0; uxIndex < uxNumberToCreate; uxIndex++ )
                {
                        xCoRoutineCreate( prvFixedDelayCoRoutine, crfFIXED_DELAY_PRIORITY, uxIndex );
                }

                /* Create the 'flash' co-routine. */
                xCoRoutineCreate( prvFlashCoRoutine, crfFLASH_PRIORITY, crfFLASH_INDEX );
        }
}
/*-----------------------------------------------------------*/

static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
/* Even though this is a co-routine the xResult variable does not need to be
static as we do not need it to maintain its state between blocks. */
signed portBASE_TYPE xResult;
/* The uxIndex parameter of the co-routine function is used as an index into
the xFlashRates array to obtain the delay period to use. */
static const portTickType xFlashRates[ crfMAX_FLASH_TASKS ] = { 150 / portTICK_RATE_MS,
                                                                                                                                200 / portTICK_RATE_MS,
                                                                                                                                250 / portTICK_RATE_MS,
                                                                                                                                300 / portTICK_RATE_MS,
                                                                                                                                350 / portTICK_RATE_MS,
                                                                                                                                400 / portTICK_RATE_MS,
                                                                                                                                450 / portTICK_RATE_MS,
                                                                                                                                500  / portTICK_RATE_MS };

        /* Co-routines MUST start with a call to crSTART. */
        crSTART( xHandle );

        for( ;; )
        {
                /* Post our uxIndex value onto the queue.  This is used as the LED to
                flash. */
                crQUEUE_SEND( xHandle, xFlashQueue, ( void * ) &uxIndex, crfPOSTING_BLOCK_TIME, &xResult );

                if( xResult != pdPASS )
                {
                        /* For the reasons stated at the top of the file we should always
                        find that we can post to the queue.  If we could not then an error
                        has occurred. */
                        xCoRoutineFlashStatus = pdFAIL;
                }

                crDELAY( xHandle, xFlashRates[ uxIndex ] );
        }

        /* Co-routines MUST end with a call to crEND. */
        crEND();
}
/*-----------------------------------------------------------*/

static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
/* Even though this is a co-routine the variable do not need to be
static as we do not need it to maintain their state between blocks. */
signed portBASE_TYPE xResult;
unsigned portBASE_TYPE uxLEDToFlash;

        /* Co-routines MUST start with a call to crSTART. */
        crSTART( xHandle );
        ( void ) uxIndex;
        
        for( ;; )
        {
                /* Block to wait for the number of the LED to flash. */
                crQUEUE_RECEIVE( xHandle, xFlashQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );                

                if( xResult != pdPASS )
                {
                        /* We would not expect to wake unless we received something. */
                        xCoRoutineFlashStatus = pdFAIL;
                }
                else
                {
                        /* We received the number of an LED to flash - flash it! */
                        vParTestToggleLED( uxLEDToFlash );
                }
        }

        /* Co-routines MUST end with a call to crEND. */
        crEND();
}
/*-----------------------------------------------------------*/

portBASE_TYPE xAreFlashCoRoutinesStillRunning( void )
{
        /* Return pdPASS or pdFAIL depending on whether an error has been detected
        or not. */
        return xCoRoutineFlashStatus;
}