/* * FreeRTOS V202212.00 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of * the Software, and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * https://www.FreeRTOS.org * https://github.com/FreeRTOS * */ /****************************************************************************** * NOTE: Windows will not be running the FreeRTOS demo threads continuously, so * do not expect to get real time behaviour from the FreeRTOS Windows port, or * this demo application. Also, the timing information in the FreeRTOS+Trace * logs have no meaningful units. See the documentation page for the Windows * port for further information: * https://www.FreeRTOS.org/FreeRTOS-Windows-Simulator-Emulator-for-Visual-Studio-and-Eclipse-MingW.html * * NOTE 2: 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 version. Console output * is used in place of the normal LED toggling. * * NOTE 3: This file only contains the source code that is specific to the * basic demo. Generic functions, such FreeRTOS hook functions, are defined * in main.c. ****************************************************************************** * * main_blinky() creates one queue, one software timer, 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. It uses vTaskDelayUntil() to create a periodic task that sends * the value 100 to the queue every 200 milliseconds (please read the notes * above regarding the accuracy of timing under Windows). * * The Queue Send Software Timer: * The timer is a one-shot timer that is reset by a key press. The timer's * period is set to two seconds - if the timer expires then its callback * function writes the value 200 to the queue. The callback function is * implemented by prvQueueSendTimerCallback() within this file. * * The Queue Receive Task: * The queue receive task is implemented by the prvQueueReceiveTask() function * in this file. prvQueueReceiveTask() waits for data to arrive on the queue. * When data is received, the task checks the value of the data, then outputs a * message to indicate if the data came from the queue send task or the queue * send software timer. * * Expected Behaviour: * - The queue send task writes to the queue every 200ms, so every 200ms the * queue receive task will output a message indicating that data was received * on the queue from the queue send task. * - The queue send software timer has a period of two seconds, and is reset * each time a key is pressed. So if two seconds expire without a key being * pressed then the queue receive task will output a message indicating that * data was received on the queue from the queue send software timer. * * NOTE: Console input and output relies on Windows system calls, which can * interfere with the execution of the FreeRTOS Windows port. This demo only * uses Windows system call occasionally. Heavier use of Windows system calls * can crash the port. */ /* Standard includes. */ #include #include /* Kernel includes. */ #include "FreeRTOS.h" #include "task.h" #include "timers.h" #include "semphr.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. The times are converted from * milliseconds to ticks using the pdMS_TO_TICKS() macro. */ #define mainTASK_SEND_FREQUENCY_MS pdMS_TO_TICKS( 200UL ) #define mainTIMER_SEND_FREQUENCY_MS pdMS_TO_TICKS( 2000UL ) /* The number of items the queue can hold at once. */ #define mainQUEUE_LENGTH ( 2 ) /* The values sent to the queue receive task from the queue send task and the * queue send software timer respectively. */ #define mainVALUE_SENT_FROM_TASK ( 100UL ) #define mainVALUE_SENT_FROM_TIMER ( 200UL ) /* This demo allows for users to perform actions with the keyboard. */ #define mainNO_KEY_PRESS_VALUE ( -1 ) #define mainRESET_TIMER_KEY ( 'r' ) /*-----------------------------------------------------------*/ /* * The tasks as described in the comments at the top of this file. */ static void prvQueueReceiveTask( void * pvParameters ); static void prvQueueSendTask( void * pvParameters ); /* * The callback function executed when the software timer expires. */ static void prvQueueSendTimerCallback( TimerHandle_t xTimerHandle ); /*-----------------------------------------------------------*/ /* The queue used by both tasks. */ static QueueHandle_t xQueue = NULL; /* A software timer that is started from the tick hook. */ static TimerHandle_t xTimer = NULL; /*-----------------------------------------------------------*/ /*** SEE THE COMMENTS AT THE TOP OF THIS FILE ***/ void main_blinky( void ) { const TickType_t xTimerPeriod = mainTIMER_SEND_FREQUENCY_MS; printf( "\r\nStarting the blinky demo. Press \'%c\' to reset the software timer used in this demo.\r\n\r\n", mainRESET_TIMER_KEY ); /* Create the queue. */ xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( uint32_t ) ); 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. */ "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. */ NULL, /* The parameter passed to the task - not used in this simple case. */ mainQUEUE_RECEIVE_TASK_PRIORITY, /* The priority assigned to the task. */ NULL ); /* The task handle is not required, so NULL is passed. */ xTaskCreate( prvQueueSendTask, "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL ); /* Create the software timer, but don't start it yet. */ xTimer = xTimerCreate( "Timer", /* The text name assigned to the software timer - for debug only as it is not used by the kernel. */ xTimerPeriod, /* The period of the software timer in ticks. */ pdTRUE, /* xAutoReload is set to pdTRUE, so this timer goes off periodically with a period of xTimerPeriod ticks. */ NULL, /* The timer's ID is not used. */ prvQueueSendTimerCallback ); /* The function executed when the timer expires. */ xTimerStart( xTimer, 0 ); /* The scheduler has not started so use a block time of 0. */ /* 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 prvQueueSendTask( void * pvParameters ) { TickType_t xNextWakeTime; const TickType_t xBlockTime = mainTASK_SEND_FREQUENCY_MS; const uint32_t ulValueToSend = mainVALUE_SENT_FROM_TASK; /* Prevent the compiler warning about the unused parameter. */ ( void ) pvParameters; /* 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, pdMS_TO_TICKS() was used to * convert a time specified in milliseconds into a time specified in ticks. * While in the Blocked state this task will not consume any CPU time. */ vTaskDelayUntil( &xNextWakeTime, xBlockTime ); /* Send to the queue - causing the queue receive task to unblock and * write to the console. 0 is used as the block time so the send operation * will not block - it shouldn't need to block as the queue should always * have at least one space at this point in the code. */ xQueueSend( xQueue, &ulValueToSend, 0U ); } } /*-----------------------------------------------------------*/ static void prvQueueSendTimerCallback( TimerHandle_t xTimerHandle ) { const uint32_t ulValueToSend = mainVALUE_SENT_FROM_TIMER; /* This is the software timer callback function. The software timer has a * period of two seconds and is reset each time a key is pressed. This * callback function will execute if the timer expires, which will only happen * if a key is not pressed for two seconds. */ /* Avoid compiler warnings resulting from the unused parameter. */ ( void ) xTimerHandle; /* Send to the queue - causing the queue receive task to unblock and * write out a message. This function is called from the timer/daemon task, so * must not block. Hence the block time is set to 0. */ xQueueSend( xQueue, &ulValueToSend, 0U ); } /*-----------------------------------------------------------*/ static void prvQueueReceiveTask( void * pvParameters ) { uint32_t ulReceivedValue; /* Prevent the compiler warning about the unused parameter. */ ( void ) pvParameters; for( ; ; ) { /* Wait until something arrives in the queue - this task will block * indefinitely provided INCLUDE_vTaskSuspend is set to 1 in * FreeRTOSConfig.h. It will not use any CPU time while it is in the * Blocked state. */ xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY ); /* Enter critical section to use printf. Not doing this could potentially cause * a deadlock if the FreeRTOS simulator switches contexts and another task * tries to call printf - it should be noted that use of printf within * the FreeRTOS simulator is unsafe, but used here for simplicity. */ taskENTER_CRITICAL(); { /* To get here something must have been received from the queue, but * is it an expected value? Normally calling printf() from a task is not * a good idea. Here there is lots of stack space and only one task is * using console IO so it is ok. However, note the comments at the top of * this file about the risks of making Windows system calls (such as * console output) from a FreeRTOS task. */ if( ulReceivedValue == mainVALUE_SENT_FROM_TASK ) { printf( "Message received from task - idle time %llu%%\r\n", ulTaskGetIdleRunTimePercent() ); } else if( ulReceivedValue == mainVALUE_SENT_FROM_TIMER ) { printf( "Message received from software timer\r\n" ); } else { printf( "Unexpected message\r\n" ); } } taskEXIT_CRITICAL(); } } /*-----------------------------------------------------------*/ /* Called from prvKeyboardInterruptSimulatorTask(), which is defined in main.c. */ void vBlinkyKeyboardInterruptHandler( int xKeyPressed ) { /* Handle keyboard input. */ switch( xKeyPressed ) { case mainRESET_TIMER_KEY: if( xTimer != NULL ) { /* Critical section around printf to prevent a deadlock * on context switch. */ taskENTER_CRITICAL(); { printf( "\r\nResetting software timer.\r\n\r\n" ); } taskEXIT_CRITICAL(); /* Reset the software timer. */ xTimerReset( xTimer, portMAX_DELAY ); } break; default: break; } }