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357 lines
15 KiB
C
357 lines
15 KiB
C
/*
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FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS books - available as PDF or paperback *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/*
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This simple demo project runs on the STM32 Discovery board, which is
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populated with an STM32F100RB Cortex-M3 microcontroller. The discovery board
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makes an ideal low cost evaluation platform, but the 8K of RAM provided on the
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STM32F100RB does not allow the simple application to demonstrate all of all the
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FreeRTOS kernel features. Therefore, this simple demo only actively
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demonstrates task, queue, timer and interrupt functionality. In addition, the
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demo is configured to include malloc failure, idle and stack overflow hook
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functions.
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The idle hook function:
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The idle hook function queries the amount of FreeRTOS heap space that is
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remaining (see vApplicationIdleHook() defined in this file). The demo
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application is configured use 7K or the available 8K of RAM as the FreeRTOS heap.
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Memory is only allocated from this heap during initialisation, and this demo
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only actually uses 1.6K bytes of the configured 7K available - leaving 5.4K
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bytes of heap space unallocated.
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The main() Function:
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main() creates one software timer, one queue, and two tasks. It then starts the
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scheduler.
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The Queue Send Task:
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The queue send task is implemented by the prvQueueSendTask() function in this
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file. prvQueueSendTask() sits in a loop that causes it to repeatedly block for
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200 milliseconds, before sending the value 100 to the queue that was created
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within main(). Once the value is sent, the task loops back around to block for
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another 200 milliseconds.
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The Queue Receive Task:
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The queue receive task is implemented by the prvQueueReceiveTask() function
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in this file. prvQueueReceiveTask() sits in a loop that causes repeatedly
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attempt to read data from the queue that was created within main(). When data
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is received, the task checks the value of the data, and if the value equals
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the expected 100, toggles the green LED. The 'block time' parameter passed to
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the queue receive function specifies that the task should be held in the Blocked
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state indefinitely to wait for data to be available on the queue. The queue
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receive task will only leave the Blocked state when the queue send task writes
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to the queue. As the queue send task writes to the queue every 200
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milliseconds, the queue receive task leaves the Blocked state every 200
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milliseconds, and therefore toggles the green LED every 200 milliseconds.
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The LED Software Timer and the Button Interrupt:
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The user button B1 is configured to generate an interrupt each time it is
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pressed. The interrupt service routine switches the red LED on, and resets the
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LED software timer. The LED timer has a 5000 millisecond (5 second) period, and
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uses a callback function that is defined to just turn the red LED off.
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Therefore, pressing the user button will turn the red LED on, and the LED will
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remain on until a full five seconds pass without the button being pressed.
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*/
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/* Kernel includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "queue.h"
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#include "timers.h"
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/* Microsemi drivers/libraries includes. */
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#include "mss_gpio.h"
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#include "mss_watchdog.h"
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/* Common demo includes. */
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#include "partest.h"
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/* Priorities at which the tasks are created. */
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#define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )
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#define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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/* The rate at which data is sent to the queue, specified in milliseconds, and
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converted to ticks using the portTICK_RATE_MS constant. */
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#define mainQUEUE_SEND_FREQUENCY_MS ( 200 / portTICK_RATE_MS )
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/* The number of items the queue can hold. This is 1 as the receive task
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will remove items as they are added, meaning the send task should always find
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the queue empty. */
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#define mainQUEUE_LENGTH ( 1 )
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#define mainTASK_CONTROLLED_LED 0x01UL
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#define mainTIMER_CONTROLLED_LED 0x02UL
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/*-----------------------------------------------------------*/
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/*
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* Setup the NVIC, LED outputs, and button inputs.
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*/
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static void prvSetupHardware( void );
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/*
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* The tasks as described in the comments at the top of this file.
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*/
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static void prvQueueReceiveTask( void *pvParameters );
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static void prvQueueSendTask( void *pvParameters );
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/*
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* The LED timer callback function. This does nothing but switch the red LED
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* off.
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*/
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static void vLEDTimerCallback( xTimerHandle xTimer );
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/*-----------------------------------------------------------*/
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/* The queue used by both tasks. */
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static xQueueHandle xQueue = NULL;
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/* The LED software timer. This uses vLEDTimerCallback() as its callback
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function. */
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static xTimerHandle xLEDTimer = NULL;
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/*-----------------------------------------------------------*/
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int main(void)
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{
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/* Configure the NVIC, LED outputs and button inputs. */
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prvSetupHardware();
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/* Create the queue. */
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xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) );
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if( xQueue != NULL )
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{
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/* Start the two tasks as described in the comments at the top of this
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file. */
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xTaskCreate( prvQueueReceiveTask, ( signed char * ) "Rx", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_RECEIVE_TASK_PRIORITY, NULL );
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xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL );
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/* Create the software timer that is responsible for turning off the LED
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if the button is not pushed within 5000ms, as described at the top of
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this file. */
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xLEDTimer = xTimerCreate( ( const signed char * ) "LEDTimer", /* A text name, purely to help debugging. */
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( 5000 / portTICK_RATE_MS ), /* The timer period, in this case 5000ms (5s). */
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pdFALSE, /* This is a one shot timer, so xAutoReload is set to pdFALSE. */
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( void * ) 0, /* The ID is not used, so can be set to anything. */
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vLEDTimerCallback /* The callback function that switches the LED off. */
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);
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/* Start the tasks and timer running. */
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vTaskStartScheduler();
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}
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/* If all is well, the scheduler will now be running, and the following line
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will never be reached. If the following line does execute, then there was
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insufficient FreeRTOS heap memory available for the idle and/or timer tasks
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to be created. See the memory management section on the FreeRTOS web site
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for more details. */
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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static void vLEDTimerCallback( xTimerHandle xTimer )
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{
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/* The timer has expired - so no button pushes have occurred in the last
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five seconds - turn the LED off. NOTE - accessing the LED port should use
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a critical section because it is accessed from multiple tasks, and the
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button interrupt - in this trivial case, for simplicity, the critical
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section is omitted. */
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ulGPIOState |= mainTIMER_CONTROLLED_LED;
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MSS_GPIO_set_outputs( ulGPIOState );
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}
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/*-----------------------------------------------------------*/
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/* The ISR executed when the user button is pushed. */
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void GPIO8_IRQHandler( void )
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{
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* The button was pushed, so ensure the LED is on before resetting the
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LED timer. The LED timer will turn the LED off if the button is not
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pushed within 5000ms. */
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ulGPIOState &= ~mainTIMER_CONTROLLED_LED;
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MSS_GPIO_set_outputs( ulGPIOState );
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/* This interrupt safe FreeRTOS function can be called from this interrupt
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because the interrupt priority is below the
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configMAX_SYSCALL_INTERRUPT_PRIORITY setting in FreeRTOSConfig.h. */
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xTimerResetFromISR( xLEDTimer, &xHigherPriorityTaskWoken );
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/* Clear the interrupt before leaving. */
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MSS_GPIO_clear_irq( MSS_GPIO_8 );
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/* If calling xTimerResetFromISR() caused a task (in this case the timer
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service/daemon task) to unblock, and the unblocked task has a priority
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higher than or equal to the task that was interrupted, then
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xHigherPriorityTaskWoken will now be set to pdTRUE, and calling
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portEND_SWITCHING_ISR() will ensure the unblocked task runs next. */
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portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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}
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/*-----------------------------------------------------------*/
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static void prvQueueSendTask( void *pvParameters )
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{
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portTickType xNextWakeTime;
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const unsigned long ulValueToSend = 100UL;
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/* Initialise xNextWakeTime - this only needs to be done once. */
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xNextWakeTime = xTaskGetTickCount();
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for( ;; )
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{
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/* Place this task in the blocked state until it is time to run again.
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The block time is specified in ticks, the constant used converts ticks
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to ms. While in the Blocked state this task will not consume any CPU
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time. */
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vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
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/* Send to the queue - causing the queue receive task to unblock and
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toggle an LED. 0 is used as the block time so the sending operation
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will not block - it shouldn't need to block as the queue should always
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be empty at this point in the code. */
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xQueueSend( xQueue, &ulValueToSend, 0 );
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}
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}
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/*-----------------------------------------------------------*/
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static void prvQueueReceiveTask( void *pvParameters )
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{
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unsigned long ulReceivedValue;
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for( ;; )
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{
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/* Wait until something arrives in the queue - this task will block
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indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
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FreeRTOSConfig.h. */
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xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
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/* To get here something must have been received from the queue, but
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is it the expected value? If it is, toggle the green LED. */
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if( ulReceivedValue == 100UL )
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{
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/* NOTE - accessing the LED port should use a critical section
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because it is accessed from multiple tasks, and the button interrupt
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- in this trivial case, for simplicity, the critical section is
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omitted. */
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if( ( ulGPIOState & mainTASK_CONTROLLED_LED ) != 0 )
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{
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ulGPIOState &= ~mainTASK_CONTROLLED_LED;
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}
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else
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{
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ulGPIOState |= mainTASK_CONTROLLED_LED;
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}
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MSS_GPIO_set_outputs( ulGPIOState );
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}
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}
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}
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/*-----------------------------------------------------------*/
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static void prvSetupHardware( void )
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{
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/* Disable the Watch Dog Timer */
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MSS_WD_disable( );
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/* Configure the GPIO for the LEDs. */
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vParTestInitialise();
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/* Setup the GPIO and the NVIC for the switch used in this simple demo. */
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NVIC_EnableIRQ( GPIO8_IRQn );
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MSS_GPIO_config( MSS_GPIO_8, MSS_GPIO_INPUT_MODE | MSS_GPIO_IRQ_EDGE_NEGATIVE );
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MSS_GPIO_enable_irq( MSS_GPIO_8 );
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}
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/*-----------------------------------------------------------*/
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void vApplicationMallocFailedHook( void )
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{
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/* Called if a call to pvPortMalloc() fails because there is insufficient
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free memory available in the FreeRTOS heap. pvPortMalloc() is called
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internally by FreeRTOS API functions that create tasks, queues, software
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timers, and semaphores. The size of the FreeRTOS heap is set by the
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configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed char *pcTaskName )
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{
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( void ) pcTaskName;
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( void ) pxTask;
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/* Run time stack overflow checking is performed if
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configconfigCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2. This hook
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function is called if a stack overflow is detected. */
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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void vApplicationIdleHook( void )
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{
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volatile size_t xFreeStackSpace;
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/* This function is called on each cycle of the idle task. In this case it
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does nothing useful, other than report the amout of FreeRTOS heap that
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remains unallocated. */
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xFreeStackSpace = xPortGetFreeHeapSize();
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if( xFreeStackSpace > 100 )
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{
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/* By now, the kernel has allocated everything it is going to, so
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if there is a lot of heap remaining unallocated then
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the value of configTOTAL_HEAP_SIZE in FreeRTOSConfig.h can be
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reduced accordingly. */
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}
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}
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