2 FreeRTOS V7.5.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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65 /* Scheduler includes. */
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66 #include "FreeRTOS.h"
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70 /* Demo includes. */
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74 * The LCD is written to by more than one task so is controlled by this
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75 * 'gatekeeper' task. This is the only task that is actually permitted to
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76 * access the LCD directly. Other tasks wanting to display a message send
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77 * the message to the gatekeeper.
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79 static void vLCDTask( void *pvParameters );
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82 * Setup the peripherals required to communicate with the LCD.
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84 static void prvSetupLCD( void );
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87 * Move to the first (0) or second (1) row of the LCD.
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89 static void prvLCDGotoRow( unsigned portSHORT usRow );
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92 * Write a string of text to the LCD.
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94 static void prvLCDPutString( portCHAR *pcString );
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99 static void prvLCDClear( void );
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101 /*-----------------------------------------------------------*/
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103 /* Brief delay to permit the LCD to catch up with commands. */
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104 #define lcdSHORT_DELAY 3
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106 /* SFR that seems to be missing from the standard header files. */
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107 #define PMAEN *( ( unsigned short * ) 0x60c )
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109 /* LCD commands. */
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110 #define lcdDEFAULT_FUNCTION 0x3c
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111 #define lcdDISPLAY_CONTROL 0x0c
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112 #define lcdCLEAR_DISPLAY 0x01
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113 #define lcdENTRY_MODE 0x06
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115 /* The length of the queue used to send messages to the LCD gatekeeper task. */
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116 #define lcdQUEUE_SIZE 3
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117 /*-----------------------------------------------------------*/
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119 /* The queue used to send messages to the LCD task. */
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120 xQueueHandle xLCDQueue;
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123 /*-----------------------------------------------------------*/
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125 xQueueHandle xStartLCDTask( void )
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127 /* Create the queue used by the LCD task. Messages for display on the LCD
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128 are received via this queue. */
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129 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ) );
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131 /* Start the task that will write to the LCD. The LCD hardware is
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132 initialised from within the task itself so delays can be used. */
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133 xTaskCreate( vLCDTask, ( signed portCHAR * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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137 /*-----------------------------------------------------------*/
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139 static void prvLCDGotoRow( unsigned portSHORT usRow )
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152 vTaskDelay( lcdSHORT_DELAY );
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154 /*-----------------------------------------------------------*/
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156 static void prvLCDPutString( portCHAR *pcString )
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158 /* Write out each character with appropriate delay between each. */
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162 PMDIN1 = *pcString;
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164 vTaskDelay( lcdSHORT_DELAY );
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167 /*-----------------------------------------------------------*/
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169 static void prvLCDClear( void )
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171 /* Clear the display. */
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173 PMDIN1 = lcdCLEAR_DISPLAY;
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174 vTaskDelay( lcdSHORT_DELAY );
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176 /*-----------------------------------------------------------*/
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178 static void prvSetupLCD( void )
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180 /* Setup the PMP. */
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185 vTaskDelay( lcdSHORT_DELAY );
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187 /* Set the default function. */
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188 PMDIN1 = lcdDEFAULT_FUNCTION;
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189 vTaskDelay( lcdSHORT_DELAY );
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191 /* Set the display control. */
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192 PMDIN1 = lcdDISPLAY_CONTROL;
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193 vTaskDelay( lcdSHORT_DELAY );
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195 /* Clear the display. */
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196 PMDIN1 = lcdCLEAR_DISPLAY;
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197 vTaskDelay( lcdSHORT_DELAY );
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199 /* Set the entry mode. */
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200 PMDIN1 = lcdENTRY_MODE;
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201 vTaskDelay( lcdSHORT_DELAY );
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203 /*-----------------------------------------------------------*/
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205 static void vLCDTask( void *pvParameters )
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207 xLCDMessage xMessage;
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208 unsigned portSHORT usRow = 0;
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210 /* Remove compiler warnigns. */
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211 ( void ) pvParameters;
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213 /* Initialise the hardware. This uses delays so must not be called prior
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214 to the scheduler being started. */
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217 /* Welcome message. */
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218 prvLCDPutString( "www.FreeRTOS.org" );
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222 /* Wait for a message to arrive that requires displaying. */
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223 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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225 /* Clear the current display value. */
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228 /* Switch rows each time so we can see that the display is still being
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230 prvLCDGotoRow( usRow & 0x01 );
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232 prvLCDPutString( xMessage.pcMessage );
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234 /* Delay the requested amount of time to ensure the text just written
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235 to the LCD is not overwritten. */
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236 vTaskDelay( xMessage.xMinDisplayTime );
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