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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [dsPIC_MPLAB/] [lcd.c] - Blame information for rev 604

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1 591 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 lcdVERY_SHORT_DELAY     ( 1 )
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#define lcdSHORT_DELAY          ( 4 / portTICK_RATE_MS )
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#define lcdLONG_DELAY           ( 15 / portTICK_RATE_MS )
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/* LCD commands. */
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#define lcdCLEAR                        ( 0x01 )
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#define lcdHOME                         ( 0x02 )
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#define lcdLINE2                        ( 0xc0 )
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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 R/W signal. */
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#define  lcdRW  LATDbits.LATD5       
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/* LCD lcdRS signal. */
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#define  lcdRS  LATBbits.LATB15      
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/* LCD lcdE signal . */
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#define  lcdE   LATDbits.LATD4       
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/* Control signal pin direction. */
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#define  RW_TRIS        TRISDbits.TRISD5 
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#define  RS_TRIS        TRISBbits.TRISB15
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#define  E_TRIS         TRISDbits.TRISD4
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/* Port for LCD data */
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#define  lcdDATA      LATE           
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#define  lcdDATAPORT  PORTE
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/* I/O setup for data Port. */
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#define  TRISDATA  TRISE          
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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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static void prvLCDCommand( portCHAR cCommand );
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static void prvLCDData( portCHAR cChar );
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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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                prvLCDCommand( lcdHOME );
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        }
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        else
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        {
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                prvLCDCommand( lcdLINE2 );
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        }
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}
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/*-----------------------------------------------------------*/
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static void prvLCDCommand( portCHAR cCommand )
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{
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        /* Prepare RD0 - RD7. */
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        lcdDATA &= 0xFF00;
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        /* Command byte to lcd. */
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    lcdDATA |= cCommand;
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        /* Ensure lcdRW is 0. */
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        lcdRW = 0;
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    lcdRS = 0;
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        /* Toggle lcdE line. */
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    lcdE = 1;
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    vTaskDelay( lcdVERY_SHORT_DELAY );
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    lcdE = 0;
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        vTaskDelay( lcdSHORT_DELAY );
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}
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/*-----------------------------------------------------------*/
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static void prvLCDData( portCHAR cChar )
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{
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        /* ensure lcdRW is 0. */
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        lcdRW = 0;
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        /* Assert register select to 1. */
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    lcdRS = 1;
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        /* Prepare RD0 - RD7. */
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        lcdDATA &= 0xFF00;
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        /* Data byte to lcd. */
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    lcdDATA |= cChar;
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    lcdE = 1;
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        Nop();
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    Nop();
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    Nop();
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        /* Toggle lcdE signal. */
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    lcdE = 0;
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        /* Negate register select to 0. */
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    lcdRS = 0;
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        vTaskDelay( lcdVERY_SHORT_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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                prvLCDData( *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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        prvLCDCommand( lcdCLEAR );
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}
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/*-----------------------------------------------------------*/
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static void prvSetupLCD( void )
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{
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        /* Wait for proper power up. */
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        vTaskDelay( lcdLONG_DELAY );
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        /* Set initial states for the data and control pins */
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        LATE &= 0xFF00;
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        /* R/W state set low. */
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    lcdRW = 0;
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        /* lcdRS state set low. */
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        lcdRS = 0;
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        /* lcdE state set low. */
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        lcdE = 0;
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        /* Set data and control pins to outputs */
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        TRISE &= 0xFF00;
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        /* lcdRW pin set as output. */
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        RW_TRIS = 0;
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        /* lcdRS pin set as output. */
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        RS_TRIS = 0;
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        /* lcdE pin set as output. */
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        E_TRIS = 0;
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        /* 1st LCD initialization sequence */
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        lcdDATA &= 0xFF00;
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    lcdDATA |= 0x0038;
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    lcdE = 1;
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    Nop();
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    Nop();
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    Nop();
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        /* Toggle lcdE signal. */
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    lcdE = 0;
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        vTaskDelay( lcdSHORT_DELAY );
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        vTaskDelay( lcdSHORT_DELAY );
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        vTaskDelay( lcdSHORT_DELAY );
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        /* 2nd LCD initialization sequence */
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        lcdDATA &= 0xFF00;
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    lcdDATA |= 0x0038;
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    lcdE = 1;
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    Nop();
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    Nop();
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    Nop();
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        /* Toggle lcdE signal. */
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    lcdE = 0;
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    vTaskDelay( lcdSHORT_DELAY );
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        /* 3rd LCD initialization sequence */
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        lcdDATA &= 0xFF00;
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    lcdDATA |= 0x0038;
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    lcdE = 1;
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    Nop();
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    Nop();
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    Nop();
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        /* Toggle lcdE signal. */
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    lcdE = 0;
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        vTaskDelay( lcdSHORT_DELAY );
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        /* Function set. */
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    prvLCDCommand( 0x38 );
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        /* Display on/off control, cursor blink off (0x0C). */
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    prvLCDCommand( 0x0C );
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        /* Entry mode set (0x06). */
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    prvLCDCommand( 0x06 );
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        prvLCDCommand( lcdCLEAR );
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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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321
        /* 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. */
326
        prvLCDPutString( "www.FreeRTOS.org" );
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        for( ;; )
329
        {
330
                /* Wait for a message to arrive that requires displaying. */
331
                while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
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333
                /* 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. */
338
                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
343
                to the LCD is not overwritten. */
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                vTaskDelay( xMessage.xMinDisplayTime );
345
        }
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}
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