*/\r
\r
/******************************************************************************\r
- * NOTE 1: The Win32 port is a simulation (or is that emulation?) only! Do not\r
- * expect to get real time behaviour from the Win32 port or this demo\r
- * application. It is provided as a convenient development and demonstration\r
- * test bed only. This was tested using Windows XP on a dual core laptop.\r
- *\r
- * Windows will not be running the FreeRTOS simulator threads continuously, so\r
- * the timing information in the FreeRTOS+Trace logs have no meaningful units.\r
- * See the documentation page for the Windows simulator for an explanation of\r
- * the slow timing:\r
+ * NOTE 1: Do not expect to get real time behaviour from the Win32 port or this\r
+ * demo application. It is provided as a convenient development and\r
+ * demonstration test bed only. Windows will not be running the FreeRTOS\r
+ * threads continuously, so the timing information in the FreeRTOS+Trace logs\r
+ * have no meaningful units. See the documentation page for the Windows\r
+ * simulator for further explanation:\r
* http://www.freertos.org/FreeRTOS-Windows-Simulator-Emulator-for-Visual-Studio-and-Eclipse-MingW.html\r
* - READ THE WEB DOCUMENTATION FOR THIS PORT FOR MORE INFORMATION ON USING IT -\r
*\r
* in main.c.\r
******************************************************************************\r
*\r
- * main_blinky() creates one queue, and two tasks. It then starts the\r
- * scheduler.\r
+ * main_blinky() creates one queue, one software timer, and two tasks. It then\r
+ * starts the scheduler.\r
*\r
* The Queue Send Task:\r
* The queue send task is implemented by the prvQueueSendTask() function in\r
- * this file. prvQueueSendTask() sits in a loop that causes it to repeatedly\r
- * block for 200 (simulated as far as the scheduler is concerned, but in\r
- * reality much longer - see notes above) milliseconds, before sending the\r
- * value 100 to the queue that was created within main_blinky(). Once the\r
- * value is sent, the task loops back around to block for another 200\r
- * (simulated) milliseconds.\r
+ * this file. It uses vTaskDelayUntil() to create a period task that sends the\r
+ * value 100 to the queue every 200 milliseconds (please read the notes above\r
+ * regarding the accuracy of timing under Windows).\r
+ *\r
+ * The Queue Send Software Timer:\r
+ * The timer is a one-shot timer that is reset by a key press. The timer's\r
+ * period is set to two seconds - if the timer expires then its callback\r
+ * function writes the value 200 to the queue. The callback function is\r
+ * implemented by prvQueueSendTimerCallback() within this file.\r
*\r
* The Queue Receive Task:\r
* The queue receive task is implemented by the prvQueueReceiveTask() function\r
- * in this file. prvQueueReceiveTask() sits in a loop where it repeatedly\r
- * blocks on attempts to read data from the queue that was created within\r
- * main_blinky(). When data is received, the task checks the value of the\r
- * data, and if the value equals the expected 100, outputs a message. The\r
- * 'block time' parameter passed to the queue receive function specifies that\r
- * the task should be held in the Blocked state indefinitely to wait for data\r
- * to be available on the queue. The queue receive task will only leave the\r
- * Blocked state when the queue send task writes to the queue. As the queue\r
- * send task writes to the queue every 200 (simulated - see notes above)\r
- * milliseconds, the queue receive task leaves the Blocked state every 200\r
- * milliseconds, and therefore outputs a message every 200 milliseconds.\r
+ * in this file. prvQueueReceiveTask() waits for data to arrive on the queue.\r
+ * When data is received, the task checks the value of the data, then outputs a\r
+ * message to indicate if the data came from the queue send task or the queue\r
+ * send software timer. As the queue send task writes to the queue every 200ms,\r
+ * the queue receive task will print a message indicating that it received data\r
+ * from the queue send task every 200ms. The queue receive task will print a\r
+ * message indicating that it received data from the queue send software timer\r
+ * 2 seconds after a key was last pressed.\r
*/\r
\r
/* Standard includes. */\r
#include <stdio.h>\r
+#include <conio.h>\r
\r
/* Kernel includes. */\r
#include "FreeRTOS.h"\r
#include "task.h"\r
+#include "timers.h"\r
#include "semphr.h"\r
\r
/* Priorities at which the tasks are created. */\r
#define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )\r
#define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )\r
\r
-/* The rate at which data is sent to the queue. The 200ms value is converted\r
-to ticks using the portTICK_PERIOD_MS constant. */\r
-#define mainQUEUE_SEND_FREQUENCY_MS ( 200 / portTICK_PERIOD_MS )\r
+/* The rate at which data is sent to the queue. The times are converted from\r
+milliseconds to ticks by the pdMS_TO_TICKS() macro where they are used. */\r
+#define mainTASK_SEND_FREQUENCY_MS 200\r
+#define mainTIMER_SEND_FREQUENCY_MS 2000\r
\r
-/* The number of items the queue can hold. This is 1 as the receive task\r
-will remove items as they are added, meaning the send task should always find\r
-the queue empty. */\r
-#define mainQUEUE_LENGTH ( 1 )\r
+/* The number of items the queue can hold. */\r
+#define mainQUEUE_LENGTH ( 2 )\r
\r
/* Values passed to the two tasks just to check the task parameter\r
functionality. */\r
#define mainQUEUE_SEND_PARAMETER ( 0x1111UL )\r
#define mainQUEUE_RECEIVE_PARAMETER ( 0x22UL )\r
\r
+/* The values sent to the queue receive task from the queue send task and the\r
+queue send software timer respectively. */\r
+#define mainVALUE_SENT_FROM_TASK ( 100UL )\r
+#define mainVALUE_SENT_FROM_TIMER ( 200UL )\r
+\r
/*-----------------------------------------------------------*/\r
\r
/*\r
static void prvQueueReceiveTask( void *pvParameters );\r
static void prvQueueSendTask( void *pvParameters );\r
\r
+/*\r
+ * The callback function executed when the software timer expires.\r
+ */\r
+static void prvQueueSendTimerCallback( TimerHandle_t xTimerHandle );\r
+\r
/*-----------------------------------------------------------*/\r
\r
/* The queue used by both tasks. */\r
static QueueHandle_t xQueue = NULL;\r
\r
+/* A software timer that is started from the tick hook. */\r
+static TimerHandle_t xTimer = NULL;\r
+\r
/*-----------------------------------------------------------*/\r
\r
void main_blinky( void )\r
{\r
+const TickType_t xTimerPeriod = pdMS_TO_TICKS( mainTIMER_SEND_FREQUENCY_MS );\r
+\r
/* Create the queue. */\r
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) );\r
\r
\r
xTaskCreate( prvQueueSendTask, "TX", configMINIMAL_STACK_SIZE, ( void * ) mainQUEUE_SEND_PARAMETER, mainQUEUE_SEND_TASK_PRIORITY, NULL );\r
\r
+ /* Create the software timer, but don't start it yet. */\r
+ xTimer = xTimerCreate( "Timer", /* The text name assigned to the software timer - for debug only as it is not used by the kernel. */\r
+ xTimerPeriod, /* The period of the software timer in ticks. */\r
+ pdFALSE, /* xAutoReload is set to pdFALSE, so this is a one shot timer. */\r
+ NULL, /* The timer's ID is not used. */\r
+ prvQueueSendTimerCallback );/* The function executed when the timer expires. */\r
+\r
/* Start the tasks and timer running. */\r
vTaskStartScheduler();\r
}\r
static void prvQueueSendTask( void *pvParameters )\r
{\r
TickType_t xNextWakeTime;\r
-const unsigned long ulValueToSend = 100UL;\r
-const TickType_t xBlockTime = pdMS_TO_TICKS( mainQUEUE_SEND_FREQUENCY_MS );\r
+const TickType_t xBlockTime = pdMS_TO_TICKS( mainTASK_SEND_FREQUENCY_MS );\r
+const uint32_t ulValueToSend = mainVALUE_SENT_FROM_TASK;\r
\r
/* Remove compiler warning in the case that configASSERT() is not\r
defined. */\r
/* Send to the queue - causing the queue receive task to unblock and\r
toggle the LED. 0 is used as the block time so the sending operation\r
will not block - it shouldn't need to block as the queue should always\r
- be empty at this point in the code. */\r
+ have at least one space at this point in the code. */\r
xQueueSend( xQueue, &ulValueToSend, 0U );\r
}\r
}\r
/*-----------------------------------------------------------*/\r
\r
+static void prvQueueSendTimerCallback( TimerHandle_t xTimerHandle )\r
+{\r
+const uint32_t ulValueToSend = mainVALUE_SENT_FROM_TIMER;\r
+\r
+ /* Avoid compiler warnings resulting from the unused parameter. */\r
+ ( void ) xTimerHandle;\r
+\r
+ /* Send to the queue - causing the queue receive task to unblock and\r
+ write out a message. This function is called from the timer/daemon task, so\r
+ must not block. Hence the block time is set to 0. */\r
+ xQueueSend( xQueue, &ulValueToSend, 0U );\r
+}\r
+/*-----------------------------------------------------------*/\r
+\r
static void prvQueueReceiveTask( void *pvParameters )\r
{\r
unsigned long ulReceivedValue;\r
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );\r
\r
/* To get here something must have been received from the queue, but\r
- is it the expected value? If it is, toggle the LED. */\r
- if( ulReceivedValue == 100UL )\r
+ is it the expected value? Normally calling printf() from a task is not\r
+ a good idea. Here there is lots of stack space and only one task is\r
+ using console IO so it is ok. */\r
+ if( ulReceivedValue == mainVALUE_SENT_FROM_TASK )\r
+ {\r
+ printf( "Message received from task\r\n" );\r
+ }\r
+ else if( ulReceivedValue == mainVALUE_SENT_FROM_TIMER )\r
+ {\r
+ printf( "Message received from software timer\r\n" );\r
+ }\r
+ else\r
+ {\r
+ printf( "Unexpected message\r\n" );\r
+ }\r
+\r
+ /* Reset the timer if a key has been pressed. The timer will write\r
+ mainVALUE_SENT_FROM_TIMER to the queue when it expires. */\r
+ if( _kbhit() != 0 )\r
{\r
- /* Normally calling printf() from a task is not a good idea. Here\r
- there is lots of stack space and only one task is using console IO\r
- so it is ok. */\r
- printf( "Message received\r\n" );\r
- ulReceivedValue = 0U;\r
+ /* Remove the key from the input buffer. */\r
+ ( void ) _getch();\r
+\r
+ /* Reset the software timer. */\r
+ xTimerReset( xTimer, portMAX_DELAY );\r
}\r
}\r
}\r
/*-----------------------------------------------------------*/\r
\r
+\r
projects / freertos / blobdiff