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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [PIC24_MPLAB/] [lcd.c] - Blame information for rev 615

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1 587 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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    *                                                                         *
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.
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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    the terms of the GNU General Public License (version 2) as published by the
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    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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    ***NOTE*** The exception to the GPL is included to allow you to distribute
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    a combined work that includes FreeRTOS without being obliged to provide the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "queue.h"
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/* Demo includes. */
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#include "lcd.h"
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/*
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 * The LCD is written to by more than one task so is controlled by this
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 * 'gatekeeper' task.  This is the only task that is actually permitted to
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 * access the LCD directly.  Other tasks wanting to display a message send
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 * the message to the gatekeeper.
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 */
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static void vLCDTask( void *pvParameters );
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/*
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 * Setup the peripherals required to communicate with the LCD.
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 */
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static void prvSetupLCD( void );
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/*
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 * Move to the first (0) or second (1) row of the LCD.
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 */
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static void prvLCDGotoRow( unsigned portSHORT usRow );
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/*
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 * Write a string of text to the LCD.
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 */
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static void prvLCDPutString( portCHAR *pcString );
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/*
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 * Clear the LCD.
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 */
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static void prvLCDClear( void );
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/*-----------------------------------------------------------*/
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/* Brief delay to permit the LCD to catch up with commands. */
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#define lcdSHORT_DELAY          3
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/* SFR that seems to be missing from the standard header files. */
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#define PMAEN                           *( ( unsigned short * ) 0x60c )
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/* LCD commands. */
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#define lcdDEFAULT_FUNCTION     0x3c
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#define lcdDISPLAY_CONTROL      0x0c
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#define lcdCLEAR_DISPLAY        0x01
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#define lcdENTRY_MODE           0x06
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/* The length of the queue used to send messages to the LCD gatekeeper task. */
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#define lcdQUEUE_SIZE           3
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/*-----------------------------------------------------------*/
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/* The queue used to send messages to the LCD task. */
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xQueueHandle xLCDQueue;
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/*-----------------------------------------------------------*/
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xQueueHandle xStartLCDTask( void )
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{
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        /* Create the queue used by the LCD task.  Messages for display on the LCD
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        are received via this queue. */
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        xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ) );
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        /* Start the task that will write to the LCD.  The LCD hardware is
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        initialised from within the task itself so delays can be used. */
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        xTaskCreate( vLCDTask, ( signed portCHAR * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
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        return xLCDQueue;
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}
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/*-----------------------------------------------------------*/
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static void prvLCDGotoRow( unsigned portSHORT usRow )
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{
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        if( usRow == 0 )
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        {
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                PMADDR = 0x0000;
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                PMDIN1 = 0x02;
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        }
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        else
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        {
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                PMADDR = 0x0000;
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                PMDIN1 = 0xc0;
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        }
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        vTaskDelay( lcdSHORT_DELAY );
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}
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/*-----------------------------------------------------------*/
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static void prvLCDPutString( portCHAR *pcString )
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{
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        /* Write out each character with appropriate delay between each. */
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        while( *pcString )
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        {
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                PMADDR = 0x0001;
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                PMDIN1 = *pcString;
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                pcString++;
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                vTaskDelay( lcdSHORT_DELAY );
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        }
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}
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/*-----------------------------------------------------------*/
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static void prvLCDClear( void )
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{
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        /* Clear the display. */
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        PMADDR = 0x0000;
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        PMDIN1 = lcdCLEAR_DISPLAY;
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        vTaskDelay( lcdSHORT_DELAY );
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}
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/*-----------------------------------------------------------*/
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static void prvSetupLCD( void )
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{
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        /* Setup the PMP. */
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        PMCON = 0x83BF;
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        PMMODE = 0x3FF;
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        PMAEN = 1;
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        PMADDR = 0x0000;
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        vTaskDelay( lcdSHORT_DELAY );
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        /* Set the default function. */
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        PMDIN1 = lcdDEFAULT_FUNCTION;
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        vTaskDelay( lcdSHORT_DELAY );
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        /* Set the display control. */
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        PMDIN1 = lcdDISPLAY_CONTROL;
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        vTaskDelay( lcdSHORT_DELAY );
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        /* Clear the display. */
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        PMDIN1 = lcdCLEAR_DISPLAY;
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        vTaskDelay( lcdSHORT_DELAY );
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        /* Set the entry mode. */
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        PMDIN1 = lcdENTRY_MODE;
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        vTaskDelay( lcdSHORT_DELAY );
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}
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/*-----------------------------------------------------------*/
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static void vLCDTask( void *pvParameters )
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{
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xLCDMessage xMessage;
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unsigned portSHORT usRow = 0;
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        /* Initialise the hardware.  This uses delays so must not be called prior
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        to the scheduler being started. */
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        prvSetupLCD();
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        /* Welcome message. */
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        prvLCDPutString( "www.FreeRTOS.org" );
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        for( ;; )
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        {
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                /* Wait for a message to arrive that requires displaying. */
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                while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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                /* Clear the current display value. */
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                prvLCDClear();
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                /* Switch rows each time so we can see that the display is still being
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                updated. */
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                prvLCDGotoRow( usRow & 0x01 );
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                usRow++;
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                prvLCDPutString( xMessage.pcMessage );
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                /* Delay the requested amount of time to ensure the text just written
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                to the LCD is not overwritten. */
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                vTaskDelay( xMessage.xMinDisplayTime );
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        }
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}
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