20100923-V6.1.0-RC2/Demo/Common/Minimal/flash.c

@@ -0,0 +1,145 @@
+/*
+    FreeRTOS V6.1.0 - Copyright (C) 2010 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 version of flash .c is for use on systems that have limited stack space
+ * and no display facilities.  The complete version can be found in the 
+ * Demo/Common/Full directory.
+ * 
+ * Three tasks are created, each of which flash an LED at a different rate.  The first 
+ * LED flashes every 200ms, the second every 400ms, the third every 600ms.
+ *
+ * The LED flash tasks provide instant visual feedback.  They show that the scheduler 
+ * is still operational.
+ *
+ */
+
+
+#include <stdlib.h>
+
+/* Scheduler include files. */
+#include "FreeRTOS.h"
+#include "task.h"
+
+/* Demo program include files. */
+#include "partest.h"
+#include "flash.h"
+
+#define ledSTACK_SIZE		configMINIMAL_STACK_SIZE
+#define ledNUMBER_OF_LEDS	( 3 )
+#define ledFLASH_RATE_BASE	( ( portTickType ) 333 )
+
+/* Variable used by the created tasks to calculate the LED number to use, and
+the rate at which they should flash the LED. */
+static volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0;
+
+/* The task that is created three times. */
+static portTASK_FUNCTION_PROTO( vLEDFlashTask, pvParameters );
+
+/*-----------------------------------------------------------*/
+
+void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority )
+{
+signed portBASE_TYPE xLEDTask;
+
+	/* Create the three tasks. */
+	for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
+	{
+		/* Spawn the task. */
+		xTaskCreate( vLEDFlashTask, ( signed char * ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
+	}
+}
+/*-----------------------------------------------------------*/
+
+static portTASK_FUNCTION( vLEDFlashTask, pvParameters )
+{
+portTickType xFlashRate, xLastFlashTime;
+unsigned portBASE_TYPE uxLED;
+
+	/* The parameters are not used. */
+	( void ) pvParameters;
+
+	/* Calculate the LED and flash rate. */
+	portENTER_CRITICAL();
+	{
+		/* See which of the eight LED's we should use. */
+		uxLED = uxFlashTaskNumber;
+
+		/* Update so the next task uses the next LED. */
+		uxFlashTaskNumber++;
+	}
+	portEXIT_CRITICAL();
+
+	xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED );
+	xFlashRate /= portTICK_RATE_MS;
+
+	/* We will turn the LED on and off again in the delay period, so each
+	delay is only half the total period. */
+	xFlashRate /= ( portTickType ) 2;
+
+	/* We need to initialise xLastFlashTime prior to the first call to 
+	vTaskDelayUntil(). */
+	xLastFlashTime = xTaskGetTickCount();
+
+	for(;;)
+	{
+		/* Delay for half the flash period then turn the LED on. */
+		vTaskDelayUntil( &xLastFlashTime, xFlashRate );
+		vParTestToggleLED( uxLED );
+
+		/* Delay for half the flash period then turn the LED off. */
+		vTaskDelayUntil( &xLastFlashTime, xFlashRate );
+		vParTestToggleLED( uxLED );
+	}
+} /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */
+