2 FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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75 /* peripheral library include */
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78 /* Scheduler includes. */
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79 #include "FreeRTOS.h"
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83 /* Demo includes. */
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87 * The LCD is written to by more than one task so is controlled by this
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88 * 'gatekeeper' task. This is the only task that is actually permitted to
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89 * access the LCD directly. Other tasks wanting to display a message send
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90 * the message to the gatekeeper.
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92 static void vLCDTask( void *pvParameters );
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95 * Setup the peripherals required to communicate with the LCD.
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97 static void prvSetupLCD( void );
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100 * Move to the first (0) or second (1) row of the LCD.
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102 static void prvLCDGotoRow( unsigned short usRow );
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105 * Write a string of text to the LCD.
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107 static void prvLCDPutString( char *pcString );
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112 static void prvLCDClear( void );
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114 /*-----------------------------------------------------------*/
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116 /* Brief delay to permit the LCD to catch up with commands. */
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117 #define lcdVERY_SHORT_DELAY ( 1 )
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118 #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS )
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119 #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS )
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121 /* LCD specific definitions. */
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122 #define LCD_CLEAR_DISPLAY_CMD 0x01
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123 #define LCD_CURSOR_HOME_CMD 0x02
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124 #define LCD_ENTRY_MODE_CMD 0x04
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125 #define LCD_ENTRY_MODE_INCREASE 0x02
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126 #define LCD_DISPLAY_CTRL_CMD 0x08
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127 #define LCD_DISPLAY_CTRL_DISPLAY_ON 0x04
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128 #define LCD_FUNCTION_SET_CMD 0x20
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129 #define LCD_FUNCTION_SET_8_BITS 0x10
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130 #define LCD_FUNCTION_SET_2_LINES 0x08
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131 #define LCD_FUNCTION_SET_LRG_FONT 0x04
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132 #define LCD_NEW_LINE 0xC0
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133 #define LCD_COMMAND_ADDRESS 0x00
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134 #define LCD_DATA_ADDRESS 0x01
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136 /* The length of the queue used to send messages to the LCD gatekeeper task. */
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137 #define lcdQUEUE_SIZE 3
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139 /*-----------------------------------------------------------*/
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141 /* The queue used to send messages to the LCD task. */
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142 xQueueHandle xLCDQueue;
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144 /* LCD access functions. */
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145 static void prvLCDCommand( char cCommand );
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146 static void prvLCDData( char cChar );
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148 /*-----------------------------------------------------------*/
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150 xQueueHandle xStartLCDTask( void )
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152 /* Create the queue used by the LCD task. Messages for display on the LCD
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153 are received via this queue. */
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154 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ));
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156 /* Start the task that will write to the LCD. The LCD hardware is
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157 initialised from within the task itself so delays can be used. */
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158 xTaskCreate( vLCDTask, ( signed char * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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162 /*-----------------------------------------------------------*/
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164 static void prvLCDGotoRow( unsigned short usRow )
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168 prvLCDCommand( LCD_CURSOR_HOME_CMD );
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172 prvLCDCommand( LCD_NEW_LINE );
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175 /*-----------------------------------------------------------*/
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177 static void prvLCDCommand( char cCommand )
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179 PMPSetAddress( LCD_COMMAND_ADDRESS );
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180 PMPMasterWrite( cCommand );
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181 vTaskDelay( lcdSHORT_DELAY );
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183 /*-----------------------------------------------------------*/
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185 static void prvLCDData( char cChar )
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187 PMPSetAddress( LCD_DATA_ADDRESS );
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188 PMPMasterWrite( cChar );
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189 vTaskDelay( lcdVERY_SHORT_DELAY );
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191 /*-----------------------------------------------------------*/
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193 static void prvLCDPutString( char *pcString )
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195 /* Write out each character with appropriate delay between each. */
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198 prvLCDData(*pcString);
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200 vTaskDelay(lcdSHORT_DELAY);
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203 /*-----------------------------------------------------------*/
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205 static void prvLCDClear(void)
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207 prvLCDCommand(LCD_CLEAR_DISPLAY_CMD);
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209 /*-----------------------------------------------------------*/
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211 static void prvSetupLCD(void)
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213 /* Wait for proper power up. */
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214 vTaskDelay( lcdLONG_DELAY );
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216 /* Open the PMP port */
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217 mPMPOpen((PMP_ON | PMP_READ_WRITE_EN | PMP_CS2_CS1_EN |
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218 PMP_LATCH_POL_HI | PMP_CS2_POL_HI | PMP_CS1_POL_HI |
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219 PMP_WRITE_POL_HI | PMP_READ_POL_HI),
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220 (PMP_MODE_MASTER1 | PMP_WAIT_BEG_4 | PMP_WAIT_MID_15 |
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224 /* Wait for the LCD to power up correctly. */
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225 vTaskDelay( lcdLONG_DELAY );
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226 vTaskDelay( lcdLONG_DELAY );
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227 vTaskDelay( lcdLONG_DELAY );
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229 /* Set up the LCD function. */
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230 prvLCDCommand( LCD_FUNCTION_SET_CMD | LCD_FUNCTION_SET_8_BITS | LCD_FUNCTION_SET_2_LINES | LCD_FUNCTION_SET_LRG_FONT );
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232 /* Turn the display on. */
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233 prvLCDCommand( LCD_DISPLAY_CTRL_CMD | LCD_DISPLAY_CTRL_DISPLAY_ON );
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235 /* Clear the display. */
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236 prvLCDCommand( LCD_CLEAR_DISPLAY_CMD );
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237 vTaskDelay( lcdLONG_DELAY );
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239 /* Increase the cursor. */
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240 prvLCDCommand( LCD_ENTRY_MODE_CMD | LCD_ENTRY_MODE_INCREASE );
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241 vTaskDelay( lcdLONG_DELAY );
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242 vTaskDelay( lcdLONG_DELAY );
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243 vTaskDelay( lcdLONG_DELAY );
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245 /*-----------------------------------------------------------*/
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247 static void vLCDTask(void *pvParameters)
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249 xLCDMessage xMessage;
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250 unsigned short usRow = 0;
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252 /* Initialise the hardware. This uses delays so must not be called prior
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253 to the scheduler being started. */
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256 /* Welcome message. */
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257 prvLCDPutString( "www.FreeRTOS.org" );
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261 /* Wait for a message to arrive that requires displaying. */
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262 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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264 /* Clear the current display value. */
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267 /* Switch rows each time so we can see that the display is still being
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269 prvLCDGotoRow( usRow & 0x01 );
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271 prvLCDPutString( xMessage.pcMessage );
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273 /* Delay the requested amount of time to ensure the text just written
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274 to the LCD is not overwritten. */
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275 vTaskDelay( xMessage.xMinDisplayTime );
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