2 FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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52 /* peripheral library include */
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55 /* Scheduler includes. */
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56 #include "FreeRTOS.h"
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60 /* Demo includes. */
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64 * The LCD is written to by more than one task so is controlled by this
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65 * 'gatekeeper' task. This is the only task that is actually permitted to
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66 * access the LCD directly. Other tasks wanting to display a message send
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67 * the message to the gatekeeper.
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69 static void vLCDTask( void *pvParameters );
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72 * Setup the peripherals required to communicate with the LCD.
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74 static void prvSetupLCD( void );
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77 * Move to the first (0) or second (1) row of the LCD.
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79 static void prvLCDGotoRow( unsigned portSHORT usRow );
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82 * Write a string of text to the LCD.
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84 static void prvLCDPutString( portCHAR *pcString );
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89 static void prvLCDClear( void );
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91 /*-----------------------------------------------------------*/
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93 /* Brief delay to permit the LCD to catch up with commands. */
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94 #define lcdVERY_SHORT_DELAY ( 1 )
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95 #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS )
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96 #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS )
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98 /* LCD specific definitions. */
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99 #define LCD_CLEAR_DISPLAY_CMD 0x01
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100 #define LCD_CURSOR_HOME_CMD 0x02
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101 #define LCD_ENTRY_MODE_CMD 0x04
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102 #define LCD_ENTRY_MODE_INCREASE 0x02
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103 #define LCD_DISPLAY_CTRL_CMD 0x08
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104 #define LCD_DISPLAY_CTRL_DISPLAY_ON 0x04
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105 #define LCD_FUNCTION_SET_CMD 0x20
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106 #define LCD_FUNCTION_SET_8_BITS 0x10
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107 #define LCD_FUNCTION_SET_2_LINES 0x08
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108 #define LCD_FUNCTION_SET_LRG_FONT 0x04
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109 #define LCD_NEW_LINE 0xC0
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110 #define LCD_COMMAND_ADDRESS 0x00
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111 #define LCD_DATA_ADDRESS 0x01
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113 /* The length of the queue used to send messages to the LCD gatekeeper task. */
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114 #define lcdQUEUE_SIZE 3
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116 /*-----------------------------------------------------------*/
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118 /* The queue used to send messages to the LCD task. */
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119 xQueueHandle xLCDQueue;
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121 /* LCD access functions. */
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122 static void prvLCDCommand( portCHAR cCommand );
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123 static void prvLCDData( portCHAR cChar );
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125 /*-----------------------------------------------------------*/
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127 xQueueHandle xStartLCDTask( void )
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129 /* Create the queue used by the LCD task. Messages for display on the LCD
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130 are received via this queue. */
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131 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ));
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133 /* Start the task that will write to the LCD. The LCD hardware is
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134 initialised from within the task itself so delays can be used. */
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135 xTaskCreate( vLCDTask, ( signed portCHAR * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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139 /*-----------------------------------------------------------*/
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141 static void prvLCDGotoRow( unsigned portSHORT usRow )
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145 prvLCDCommand( LCD_CURSOR_HOME_CMD );
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149 prvLCDCommand( LCD_NEW_LINE );
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152 /*-----------------------------------------------------------*/
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154 static void prvLCDCommand( portCHAR cCommand )
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156 PMPSetAddress( LCD_COMMAND_ADDRESS );
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157 PMPMasterWrite( cCommand );
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158 vTaskDelay( lcdSHORT_DELAY );
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160 /*-----------------------------------------------------------*/
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162 static void prvLCDData( portCHAR cChar )
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164 PMPSetAddress( LCD_DATA_ADDRESS );
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165 PMPMasterWrite( cChar );
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166 vTaskDelay( lcdVERY_SHORT_DELAY );
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168 /*-----------------------------------------------------------*/
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170 static void prvLCDPutString( portCHAR *pcString )
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172 /* Write out each character with appropriate delay between each. */
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175 prvLCDData(*pcString);
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177 vTaskDelay(lcdSHORT_DELAY);
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180 /*-----------------------------------------------------------*/
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182 static void prvLCDClear(void)
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184 prvLCDCommand(LCD_CLEAR_DISPLAY_CMD);
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186 /*-----------------------------------------------------------*/
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188 static void prvSetupLCD(void)
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190 /* Wait for proper power up. */
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191 vTaskDelay( lcdLONG_DELAY );
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193 /* Open the PMP port */
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194 mPMPOpen((PMP_ON | PMP_READ_WRITE_EN | PMP_CS2_CS1_EN |
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195 PMP_LATCH_POL_HI | PMP_CS2_POL_HI | PMP_CS1_POL_HI |
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196 PMP_WRITE_POL_HI | PMP_READ_POL_HI),
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197 (PMP_MODE_MASTER1 | PMP_WAIT_BEG_4 | PMP_WAIT_MID_15 |
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201 /* Wait for the LCD to power up correctly. */
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202 vTaskDelay( lcdLONG_DELAY );
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203 vTaskDelay( lcdLONG_DELAY );
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204 vTaskDelay( lcdLONG_DELAY );
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206 /* Set up the LCD function. */
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207 prvLCDCommand( LCD_FUNCTION_SET_CMD | LCD_FUNCTION_SET_8_BITS | LCD_FUNCTION_SET_2_LINES | LCD_FUNCTION_SET_LRG_FONT );
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209 /* Turn the display on. */
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210 prvLCDCommand( LCD_DISPLAY_CTRL_CMD | LCD_DISPLAY_CTRL_DISPLAY_ON );
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212 /* Clear the display. */
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213 prvLCDCommand( LCD_CLEAR_DISPLAY_CMD );
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214 vTaskDelay( lcdLONG_DELAY );
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216 /* Increase the cursor. */
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217 prvLCDCommand( LCD_ENTRY_MODE_CMD | LCD_ENTRY_MODE_INCREASE );
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218 vTaskDelay( lcdLONG_DELAY );
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219 vTaskDelay( lcdLONG_DELAY );
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220 vTaskDelay( lcdLONG_DELAY );
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222 /*-----------------------------------------------------------*/
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224 static void vLCDTask(void *pvParameters)
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226 xLCDMessage xMessage;
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227 unsigned portSHORT usRow = 0;
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229 /* Initialise the hardware. This uses delays so must not be called prior
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230 to the scheduler being started. */
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233 /* Welcome message. */
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234 prvLCDPutString( "www.FreeRTOS.org" );
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238 /* Wait for a message to arrive that requires displaying. */
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239 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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241 /* Clear the current display value. */
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244 /* Switch rows each time so we can see that the display is still being
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246 prvLCDGotoRow( usRow & 0x01 );
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248 prvLCDPutString( xMessage.pcMessage );
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250 /* Delay the requested amount of time to ensure the text just written
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251 to the LCD is not overwritten. */
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252 vTaskDelay( xMessage.xMinDisplayTime );
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