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FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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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 modification 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
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
and the FreeRTOS license exception along with FreeRTOS; if not it can be
viewed here: and also obtained by
writing to Real Time Engineers Ltd., contact details for whom are available
on the FreeRTOS WEB site.
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* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong?" *
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*************************************************************************** - Documentation, books, training, latest versions,
license and Real Time Engineers Ltd. contact details. - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, and our new
fully thread aware and reentrant UDP/IP stack. - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems, who sell the code with commercial support,
indemnification and middleware, under the OpenRTOS brand. - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
* NOTE 1: This project provides two demo applications. A simple blinky style
* project, and a more comprehensive test and demo application. The
* mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting in main.c is used to select
* between the two. See the notes on using mainCREATE_SIMPLE_BLINKY_DEMO_ONLY
* in main.c. This file implements the simply blinky style version.
* NOTE 2: This file only contains the source code that is specific to the
* basic demo. Generic functions, such FreeRTOS hook functions, and functions
* required to configure the hardware, are defined in main.c.
* main_blinky() creates one queue, and two tasks. It then starts the
* scheduler.
* The Queue Send Task:
* The queue send task is implemented by the prvQueueSendTask() function in
* this file. prvQueueSendTask() sits in a loop that causes it to repeatedly
* block for 200 milliseconds, before sending the value 100 to the queue that
* was created within main_blinky(). Once the value is sent, the task loops
* back around to block for another 200 milliseconds.
* The Queue Receive Task:
* The queue receive task is implemented by the prvQueueReceiveTask() function
* in this file. prvQueueReceiveTask() sits in a loop where it repeatedly
* blocks on attempts to read data from the queue that was created within
* main_blinky(). When data is received, the task checks the value of the
* data, and if the value equals the expected 100, toggles the LED. The 'block
* time' parameter passed to the queue receive function specifies that the
* task should be held in the Blocked state indefinitely to wait for data to
* be available on the queue. The queue receive task will only leave the
* Blocked state when the queue send task writes to the queue. As the queue
* send task writes to the queue every 200 milliseconds, the queue receive
* task leaves the Blocked state every 200 milliseconds, and therefore toggles
* the LED every 200 milliseconds.
/* Standard includes. */
#include <stdio.h>
/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
/* Atmel library includes. */
#include "asf.h"
/* Common demo includes. */
#include "partest.h"
/* Priorities at which the tasks are created. */
/* The rate at which data is sent to the queue. The 200ms value is converted
to ticks using the portTICK_RATE_MS constant. */
#define mainQUEUE_SEND_FREQUENCY_MS ( 200 / portTICK_RATE_MS )
/* The number of items the queue can hold. This is 1 as the receive task
will remove items as they are added, meaning the send task should always find
the queue empty. */
#define mainQUEUE_LENGTH ( 1 )
/* Values passed to the two tasks just to check the task parameter
functionality. */
#define mainQUEUE_SEND_PARAMETER ( 0x1111UL )
#define mainQUEUE_RECEIVE_PARAMETER ( 0x22UL )
* The tasks as described in the comments at the top of this file.
static void prvQueueReceiveTask( void *pvParameters );
static void prvQueueSendTask( void *pvParameters );
* Called by main() to create the simply blinky style application if
void main_blinky( void );
/* The queue used by both tasks. */
static xQueueHandle xQueue = NULL;
void main_blinky( void )
/* Create the queue. */
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) );
if( xQueue != NULL )
/* Start the two tasks as described in the comments at the top of this
file. */
xTaskCreate( prvQueueReceiveTask, /* The function that implements the task. */
( signed char * ) "Rx", /* The text name assigned to the task - for debug only as it is not used by the kernel. */
configMINIMAL_STACK_SIZE, /* The size of the stack to allocate to the task. */
( void * ) mainQUEUE_RECEIVE_PARAMETER, /* The parameter passed to the task - just to check the functionality. */
mainQUEUE_RECEIVE_TASK_PRIORITY, /* The priority assigned to the task. */
NULL ); /* The task handle is not required, so NULL is passed. */
xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, ( void * ) mainQUEUE_SEND_PARAMETER, mainQUEUE_SEND_TASK_PRIORITY, NULL );
/* Start the tasks and timer running. */
/* If all is well, the scheduler will now be running, and the following
line will never be reached. If the following line does execute, then
there was insufficient FreeRTOS heap memory available for the idle and/or
timer tasks to be created. See the memory management section on the
FreeRTOS web site for more details. */
for( ;; );
static void prvQueueSendTask( void *pvParameters )
portTickType xNextWakeTime;
const unsigned long ulValueToSend = 100UL;
/* Check the task parameter is as expected. */
configASSERT( ( ( unsigned long ) pvParameters ) == mainQUEUE_SEND_PARAMETER );
/* Initialise xNextWakeTime - this only needs to be done once. */
xNextWakeTime = xTaskGetTickCount();
for( ;; )
/* Place this task in the blocked state until it is time to run again.
The block time is specified in ticks, the constant used converts ticks
to ms. While in the Blocked state this task will not consume any CPU
time. */
vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
/* Send to the queue - causing the queue receive task to unblock and
toggle the LED. 0 is used as the block time so the sending operation
will not block - it shouldn't need to block as the queue should always
be empty at this point in the code. */
xQueueSend( xQueue, &ulValueToSend, 0U );
static void prvQueueReceiveTask( void *pvParameters )
unsigned long ulReceivedValue;
/* Check the task parameter is as expected. */
configASSERT( ( ( unsigned long ) pvParameters ) == mainQUEUE_RECEIVE_PARAMETER );
for( ;; )
/* Wait until something arrives in the queue - this task will block
indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
FreeRTOSConfig.h. */
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
/* To get here something must have been received from the queue, but
is it the expected value? If it is, toggle the LED. */
if( ulReceivedValue == 100UL )
vParTestToggleLED( 0 );
ulReceivedValue = 0U;