2 FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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67 /* peripheral library include */
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70 /* Scheduler includes. */
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71 #include "FreeRTOS.h"
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75 /* Demo includes. */
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79 * The LCD is written to by more than one task so is controlled by this
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80 * 'gatekeeper' task. This is the only task that is actually permitted to
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81 * access the LCD directly. Other tasks wanting to display a message send
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82 * the message to the gatekeeper.
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84 static void vLCDTask( void *pvParameters );
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87 * Setup the peripherals required to communicate with the LCD.
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89 static void prvSetupLCD( void );
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92 * Move to the first (0) or second (1) row of the LCD.
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94 static void prvLCDGotoRow( unsigned short usRow );
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97 * Write a string of text to the LCD.
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99 static void prvLCDPutString( char *pcString );
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104 static void prvLCDClear( void );
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106 /*-----------------------------------------------------------*/
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108 /* Brief delay to permit the LCD to catch up with commands. */
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109 #define lcdVERY_SHORT_DELAY ( 1 )
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110 #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS )
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111 #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS )
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113 /* LCD specific definitions. */
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114 #define LCD_CLEAR_DISPLAY_CMD 0x01
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115 #define LCD_CURSOR_HOME_CMD 0x02
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116 #define LCD_ENTRY_MODE_CMD 0x04
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117 #define LCD_ENTRY_MODE_INCREASE 0x02
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118 #define LCD_DISPLAY_CTRL_CMD 0x08
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119 #define LCD_DISPLAY_CTRL_DISPLAY_ON 0x04
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120 #define LCD_FUNCTION_SET_CMD 0x20
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121 #define LCD_FUNCTION_SET_8_BITS 0x10
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122 #define LCD_FUNCTION_SET_2_LINES 0x08
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123 #define LCD_FUNCTION_SET_LRG_FONT 0x04
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124 #define LCD_NEW_LINE 0xC0
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125 #define LCD_COMMAND_ADDRESS 0x00
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126 #define LCD_DATA_ADDRESS 0x01
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128 /* The length of the queue used to send messages to the LCD gatekeeper task. */
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129 #define lcdQUEUE_SIZE 3
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131 /*-----------------------------------------------------------*/
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133 /* The queue used to send messages to the LCD task. */
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134 xQueueHandle xLCDQueue;
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136 /* LCD access functions. */
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137 static void prvLCDCommand( char cCommand );
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138 static void prvLCDData( char cChar );
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140 /*-----------------------------------------------------------*/
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142 xQueueHandle xStartLCDTask( void )
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144 /* Create the queue used by the LCD task. Messages for display on the LCD
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145 are received via this queue. */
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146 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ));
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148 /* Start the task that will write to the LCD. The LCD hardware is
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149 initialised from within the task itself so delays can be used. */
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150 xTaskCreate( vLCDTask, ( signed char * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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154 /*-----------------------------------------------------------*/
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156 static void prvLCDGotoRow( unsigned short usRow )
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160 prvLCDCommand( LCD_CURSOR_HOME_CMD );
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164 prvLCDCommand( LCD_NEW_LINE );
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167 /*-----------------------------------------------------------*/
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169 static void prvLCDCommand( char cCommand )
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171 PMPSetAddress( LCD_COMMAND_ADDRESS );
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172 PMPMasterWrite( cCommand );
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173 vTaskDelay( lcdSHORT_DELAY );
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175 /*-----------------------------------------------------------*/
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177 static void prvLCDData( char cChar )
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179 PMPSetAddress( LCD_DATA_ADDRESS );
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180 PMPMasterWrite( cChar );
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181 vTaskDelay( lcdVERY_SHORT_DELAY );
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183 /*-----------------------------------------------------------*/
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185 static void prvLCDPutString( char *pcString )
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187 /* Write out each character with appropriate delay between each. */
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190 prvLCDData(*pcString);
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192 vTaskDelay(lcdSHORT_DELAY);
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195 /*-----------------------------------------------------------*/
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197 static void prvLCDClear(void)
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199 prvLCDCommand(LCD_CLEAR_DISPLAY_CMD);
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201 /*-----------------------------------------------------------*/
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203 static void prvSetupLCD(void)
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205 /* Wait for proper power up. */
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206 vTaskDelay( lcdLONG_DELAY );
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208 /* Open the PMP port */
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209 mPMPOpen((PMP_ON | PMP_READ_WRITE_EN | PMP_CS2_CS1_EN |
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210 PMP_LATCH_POL_HI | PMP_CS2_POL_HI | PMP_CS1_POL_HI |
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211 PMP_WRITE_POL_HI | PMP_READ_POL_HI),
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212 (PMP_MODE_MASTER1 | PMP_WAIT_BEG_4 | PMP_WAIT_MID_15 |
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216 /* Wait for the LCD to power up correctly. */
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217 vTaskDelay( lcdLONG_DELAY );
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218 vTaskDelay( lcdLONG_DELAY );
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219 vTaskDelay( lcdLONG_DELAY );
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221 /* Set up the LCD function. */
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222 prvLCDCommand( LCD_FUNCTION_SET_CMD | LCD_FUNCTION_SET_8_BITS | LCD_FUNCTION_SET_2_LINES | LCD_FUNCTION_SET_LRG_FONT );
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224 /* Turn the display on. */
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225 prvLCDCommand( LCD_DISPLAY_CTRL_CMD | LCD_DISPLAY_CTRL_DISPLAY_ON );
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227 /* Clear the display. */
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228 prvLCDCommand( LCD_CLEAR_DISPLAY_CMD );
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229 vTaskDelay( lcdLONG_DELAY );
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231 /* Increase the cursor. */
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232 prvLCDCommand( LCD_ENTRY_MODE_CMD | LCD_ENTRY_MODE_INCREASE );
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233 vTaskDelay( lcdLONG_DELAY );
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234 vTaskDelay( lcdLONG_DELAY );
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235 vTaskDelay( lcdLONG_DELAY );
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237 /*-----------------------------------------------------------*/
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239 static void vLCDTask(void *pvParameters)
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241 xLCDMessage xMessage;
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242 unsigned short usRow = 0;
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244 /* Initialise the hardware. This uses delays so must not be called prior
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245 to the scheduler being started. */
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248 /* Welcome message. */
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249 prvLCDPutString( "www.FreeRTOS.org" );
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253 /* Wait for a message to arrive that requires displaying. */
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254 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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256 /* Clear the current display value. */
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259 /* Switch rows each time so we can see that the display is still being
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261 prvLCDGotoRow( usRow & 0x01 );
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263 prvLCDPutString( xMessage.pcMessage );
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265 /* Delay the requested amount of time to ensure the text just written
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266 to the LCD is not overwritten. */
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267 vTaskDelay( xMessage.xMinDisplayTime );
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