/* FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd. *************************************************************************** * * * If you are: * * * * + New to FreeRTOS, * * + Wanting to learn FreeRTOS or multitasking in general quickly * * + Looking for basic training, * * + Wanting to improve your FreeRTOS skills and productivity * * * * then take a look at the FreeRTOS books - available as PDF or paperback * * * * "Using the FreeRTOS Real Time Kernel - a Practical Guide" * * http://www.FreeRTOS.org/Documentation * * * * A pdf reference manual is also available. Both are usually delivered * * to your inbox within 20 minutes to two hours when purchased between 8am * * and 8pm GMT (although please allow up to 24 hours in case of * * exceptional circumstances). Thank you for your support! * * * *************************************************************************** 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. 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: http://www.freertos.org/a00114.html and also obtained by writing to Richard Barry, contact details for whom are available on the FreeRTOS WEB site. 1 tab == 4 spaces! 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 simple demo project runs on the STM32 Discovery board, which is * populated with an STM32F100RB Cortex-M3 microcontroller. The discovery board * makes an ideal low cost evaluation platform, but the 8K of RAM provided on the * STM32F100RB does not allow the simple application to demonstrate all of all the * FreeRTOS kernel features. Therefore, this simple demo only actively * demonstrates task, queue, timer and interrupt functionality. In addition, the * demo is configured to include malloc failure, idle and stack overflow hook * functions. * * The idle hook function: * The idle hook function queries the amount of FreeRTOS heap space that is * remaining (see vApplicationIdleHook() defined in this file). The demo * application is configured use 7K or the available 8K of RAM as the FreeRTOS heap. * Memory is only allocated from this heap during initialisation, and this demo * only actually uses 1.6K bytes of the configured 7K available - leaving 5.4K * bytes of heap space unallocated. * * The main() Function: * main() creates one software timer, 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(). 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 that causes repeatedly * attempt to read data from the queue that was created within main(). When data * is received, the task checks the value of the data, and if the value equals * the expected 100, toggles the green 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 green LED every 200 milliseconds. * * The LED Software Timer and the Button Interrupt: * The user button B1 is configured to generate an interrupt each time it is * pressed. The interrupt service routine switches the red LED on, and resets the * LED software timer. The LED timer has a 5000 millisecond (5 second) period, and * uses a callback function that is defined to just turn the red LED off. * Therefore, pressing the user button will turn the red LED on, and the LED will * remain on until a full five seconds pass without the button being pressed. */ /* Kernel includes. */ #include "FreeRTOS.h" #include "task.h" #include "queue.h" #include "timers.h" /* Microsemi drivers/libraries. */ #include "mss_gpio.h" #include "mss_watchdog.h" /* Priorities at which the tasks are created. */ #define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 ) #define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 ) /* The rate at which data is sent to the queue, specified in milliseconds, and 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 ) #define mainTASK_CONTROLLED_LED 0x01UL #define mainTIMER_CONTROLLED_LED 0x02UL /*-----------------------------------------------------------*/ /* * Setup the NVIC, LED outputs, and button inputs. */ static void prvSetupHardware( void ); /* * The tasks as described in the comments at the top of this file. */ static void prvQueueReceiveTask( void *pvParameters ); static void prvQueueSendTask( void *pvParameters ); /* * The LED timer callback function. This does nothing but switch the red LED * off. */ static void vLEDTimerCallback( xTimerHandle xTimer ); /*-----------------------------------------------------------*/ /* The queue used by both tasks. */ static xQueueHandle xQueue = NULL; /* The LED software timer. This uses vLEDTimerCallback() as its callback function. */ static xTimerHandle xLEDTimer = NULL; volatile unsigned long ulGPIOState = 0UL; /*-----------------------------------------------------------*/ int main(void) { /* Configure the NVIC, LED outputs and button inputs. */ prvSetupHardware(); /* 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, ( signed char * ) "Rx", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_RECEIVE_TASK_PRIORITY, NULL ); xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL ); /* Create the software timer that is responsible for turning off the LED if the button is not pushed within 5000ms, as described at the top of this file. */ xLEDTimer = xTimerCreate( ( const signed char * ) "LEDTimer", /* A text name, purely to help debugging. */ ( 5000 / portTICK_RATE_MS ), /* The timer period, in this case 5000ms (5s). */ pdFALSE, /* This is a one shot timer, so xAutoReload is set to pdFALSE. */ ( void * ) 0, /* The ID is not used, so can be set to anything. */ vLEDTimerCallback /* The callback function that switches the LED off. */ ); /* Start the tasks and timer running. */ vTaskStartScheduler(); } /* 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 vLEDTimerCallback( xTimerHandle xTimer ) { /* The timer has expired - so no button pushes have occurred in the last five seconds - turn the LED off. NOTE - accessing the LED port should use a critical section because it is accessed from multiple tasks, and the button interrupt - in this trivial case, for simplicity, the critical section is omitted. */ ulGPIOState |= mainTIMER_CONTROLLED_LED; MSS_GPIO_set_outputs( ulGPIOState ); } /*-----------------------------------------------------------*/ /* The ISR executed when the user button is pushed. */ void GPIO8_IRQHandler( void ) { portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; /* The button was pushed, so ensure the LED is on before resetting the LED timer. The LED timer will turn the LED off if the button is not pushed within 5000ms. */ ulGPIOState &= ~mainTIMER_CONTROLLED_LED; MSS_GPIO_set_outputs( ulGPIOState ); /* This interrupt safe FreeRTOS function can be called from this interrupt because the interrupt priority is below the configMAX_SYSCALL_INTERRUPT_PRIORITY setting in FreeRTOSConfig.h. */ xTimerResetFromISR( xLEDTimer, &xHigherPriorityTaskWoken ); /* Clear the interrupt before leaving. */ MSS_GPIO_clear_irq( MSS_GPIO_8 ); /* If calling xTimerResetFromISR() caused a task (in this case the timer service/daemon task) to unblock, and the unblocked task has a priority higher than or equal to the task that was interrupted, then xHigherPriorityTaskWoken will now be set to pdTRUE, and calling portEND_SWITCHING_ISR() will ensure the unblocked task runs next. */ portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); } /*-----------------------------------------------------------*/ static void prvQueueSendTask( void *pvParameters ) { portTickType xNextWakeTime; const unsigned long ulValueToSend = 100UL; /* 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 an 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, 0 ); } } /*-----------------------------------------------------------*/ static void prvQueueReceiveTask( void *pvParameters ) { unsigned long ulReceivedValue; 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 green LED. */ if( ulReceivedValue == 100UL ) { /* NOTE - accessing the LED port should use a critical section because it is accessed from multiple tasks, and the button interrupt - in this trivial case, for simplicity, the critical section is omitted. */ if( ( ulGPIOState & mainTASK_CONTROLLED_LED ) != 0 ) { ulGPIOState &= ~mainTASK_CONTROLLED_LED; } else { ulGPIOState |= mainTASK_CONTROLLED_LED; } MSS_GPIO_set_outputs( ulGPIOState ); } } } /*-----------------------------------------------------------*/ static void prvSetupHardware( void ) { /* Disable the Watch Dog Timer */ MSS_WD_disable( ); /* Initialise the GPIO */ MSS_GPIO_init(); /* Set up GPIO for the LEDs. */ MSS_GPIO_config( MSS_GPIO_0 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_1 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_2 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_3 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_4 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_5 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_6 , MSS_GPIO_OUTPUT_MODE ); MSS_GPIO_config( MSS_GPIO_7 , MSS_GPIO_OUTPUT_MODE ); /* All LEDs start off. */ ulGPIOState = 0xffffffffUL; MSS_GPIO_set_outputs( ulGPIOState ); /* Setup the GPIO and the NVIC for the switch used in this simple demo. */ NVIC_SetPriority( GPIO8_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY ); NVIC_EnableIRQ( GPIO8_IRQn ); MSS_GPIO_config( MSS_GPIO_8, MSS_GPIO_INPUT_MODE | MSS_GPIO_IRQ_EDGE_NEGATIVE ); MSS_GPIO_enable_irq( MSS_GPIO_8 ); } /*-----------------------------------------------------------*/ void vApplicationMallocFailedHook( void ) { /* Called if a call to pvPortMalloc() fails because there is insufficient free memory available in the FreeRTOS heap. pvPortMalloc() is called internally by FreeRTOS API functions that create tasks, queues, software timers, and semaphores. The size of the FreeRTOS heap is set by the configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */ for( ;; ); } /*-----------------------------------------------------------*/ void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed char *pcTaskName ) { ( void ) pcTaskName; ( void ) pxTask; /* Run time stack overflow checking is performed if configconfigCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2. This hook function is called if a stack overflow is detected. */ for( ;; ); } /*-----------------------------------------------------------*/ void vApplicationIdleHook( void ) { volatile size_t xFreeStackSpace; /* This function is called on each cycle of the idle task. In this case it does nothing useful, other than report the amout of FreeRTOS heap that remains unallocated. */ xFreeStackSpace = xPortGetFreeHeapSize(); if( xFreeStackSpace > 100 ) { /* By now, the kernel has allocated everything it is going to, so if there is a lot of heap remaining unallocated then the value of configTOTAL_HEAP_SIZE in FreeRTOSConfig.h can be reduced accordingly. */ } }