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 /* peripheral library include */
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68 /* Scheduler includes. */
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69 #include "FreeRTOS.h"
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73 /* Demo includes. */
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77 * The LCD is written to by more than one task so is controlled by this
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78 * 'gatekeeper' task. This is the only task that is actually permitted to
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79 * access the LCD directly. Other tasks wanting to display a message send
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80 * the message to the gatekeeper.
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82 static void vLCDTask( void *pvParameters );
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85 * Setup the peripherals required to communicate with the LCD.
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87 static void prvSetupLCD( void );
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90 * Move to the first (0) or second (1) row of the LCD.
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92 static void prvLCDGotoRow( unsigned short usRow );
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95 * Write a string of text to the LCD.
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97 static void prvLCDPutString( char *pcString );
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102 static void prvLCDClear( void );
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104 /*-----------------------------------------------------------*/
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106 /* Brief delay to permit the LCD to catch up with commands. */
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107 #define lcdVERY_SHORT_DELAY ( 1 )
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108 #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS )
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109 #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS )
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111 /* LCD specific definitions. */
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112 #define LCD_CLEAR_DISPLAY_CMD 0x01
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113 #define LCD_CURSOR_HOME_CMD 0x02
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114 #define LCD_ENTRY_MODE_CMD 0x04
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115 #define LCD_ENTRY_MODE_INCREASE 0x02
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116 #define LCD_DISPLAY_CTRL_CMD 0x08
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117 #define LCD_DISPLAY_CTRL_DISPLAY_ON 0x04
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118 #define LCD_FUNCTION_SET_CMD 0x20
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119 #define LCD_FUNCTION_SET_8_BITS 0x10
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120 #define LCD_FUNCTION_SET_2_LINES 0x08
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121 #define LCD_FUNCTION_SET_LRG_FONT 0x04
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122 #define LCD_NEW_LINE 0xC0
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123 #define LCD_COMMAND_ADDRESS 0x00
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124 #define LCD_DATA_ADDRESS 0x01
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126 /* The length of the queue used to send messages to the LCD gatekeeper task. */
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127 #define lcdQUEUE_SIZE 3
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129 /*-----------------------------------------------------------*/
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131 /* The queue used to send messages to the LCD task. */
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132 xQueueHandle xLCDQueue;
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134 /* LCD access functions. */
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135 static void prvLCDCommand( char cCommand );
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136 static void prvLCDData( char cChar );
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138 /*-----------------------------------------------------------*/
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140 xQueueHandle xStartLCDTask( void )
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142 /* Create the queue used by the LCD task. Messages for display on the LCD
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143 are received via this queue. */
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144 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ));
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146 /* Start the task that will write to the LCD. The LCD hardware is
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147 initialised from within the task itself so delays can be used. */
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148 xTaskCreate( vLCDTask, ( signed char * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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152 /*-----------------------------------------------------------*/
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154 static void prvLCDGotoRow( unsigned short usRow )
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158 prvLCDCommand( LCD_CURSOR_HOME_CMD );
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162 prvLCDCommand( LCD_NEW_LINE );
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165 /*-----------------------------------------------------------*/
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167 static void prvLCDCommand( char cCommand )
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169 PMPSetAddress( LCD_COMMAND_ADDRESS );
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170 PMPMasterWrite( cCommand );
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171 vTaskDelay( lcdSHORT_DELAY );
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173 /*-----------------------------------------------------------*/
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175 static void prvLCDData( char cChar )
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177 PMPSetAddress( LCD_DATA_ADDRESS );
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178 PMPMasterWrite( cChar );
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179 vTaskDelay( lcdVERY_SHORT_DELAY );
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181 /*-----------------------------------------------------------*/
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183 static void prvLCDPutString( char *pcString )
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185 /* Write out each character with appropriate delay between each. */
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188 prvLCDData(*pcString);
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190 vTaskDelay(lcdSHORT_DELAY);
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193 /*-----------------------------------------------------------*/
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195 static void prvLCDClear(void)
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197 prvLCDCommand(LCD_CLEAR_DISPLAY_CMD);
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199 /*-----------------------------------------------------------*/
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201 static void prvSetupLCD(void)
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203 /* Wait for proper power up. */
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204 vTaskDelay( lcdLONG_DELAY );
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206 /* Open the PMP port */
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207 mPMPOpen((PMP_ON | PMP_READ_WRITE_EN | PMP_CS2_CS1_EN |
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208 PMP_LATCH_POL_HI | PMP_CS2_POL_HI | PMP_CS1_POL_HI |
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209 PMP_WRITE_POL_HI | PMP_READ_POL_HI),
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210 (PMP_MODE_MASTER1 | PMP_WAIT_BEG_4 | PMP_WAIT_MID_15 |
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214 /* Wait for the LCD to power up correctly. */
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215 vTaskDelay( lcdLONG_DELAY );
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216 vTaskDelay( lcdLONG_DELAY );
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217 vTaskDelay( lcdLONG_DELAY );
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219 /* Set up the LCD function. */
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220 prvLCDCommand( LCD_FUNCTION_SET_CMD | LCD_FUNCTION_SET_8_BITS | LCD_FUNCTION_SET_2_LINES | LCD_FUNCTION_SET_LRG_FONT );
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222 /* Turn the display on. */
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223 prvLCDCommand( LCD_DISPLAY_CTRL_CMD | LCD_DISPLAY_CTRL_DISPLAY_ON );
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225 /* Clear the display. */
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226 prvLCDCommand( LCD_CLEAR_DISPLAY_CMD );
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227 vTaskDelay( lcdLONG_DELAY );
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229 /* Increase the cursor. */
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230 prvLCDCommand( LCD_ENTRY_MODE_CMD | LCD_ENTRY_MODE_INCREASE );
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231 vTaskDelay( lcdLONG_DELAY );
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232 vTaskDelay( lcdLONG_DELAY );
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233 vTaskDelay( lcdLONG_DELAY );
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235 /*-----------------------------------------------------------*/
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237 static void vLCDTask(void *pvParameters)
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239 xLCDMessage xMessage;
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240 unsigned short usRow = 0;
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242 /* Initialise the hardware. This uses delays so must not be called prior
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243 to the scheduler being started. */
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246 /* Welcome message. */
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247 prvLCDPutString( "www.FreeRTOS.org" );
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251 /* Wait for a message to arrive that requires displaying. */
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252 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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254 /* Clear the current display value. */
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257 /* Switch rows each time so we can see that the display is still being
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259 prvLCDGotoRow( usRow & 0x01 );
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261 prvLCDPutString( xMessage.pcMessage );
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263 /* Delay the requested amount of time to ensure the text just written
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264 to the LCD is not overwritten. */
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265 vTaskDelay( xMessage.xMinDisplayTime );
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