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244 lines
7.4 KiB
C
244 lines
7.4 KiB
C
/*
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FreeRTOS.org V4.6.1 - Copyright (C) 2003-2007 Richard Barry.
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This file is part of the FreeRTOS.org distribution.
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FreeRTOS.org is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS.org, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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Also see http://www.SafeRTOS.com a version that has been certified for use
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in safety critical systems, plus commercial licensing, development and
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support options.
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***************************************************************************
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*/
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/* peripheral library include */
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#include <plib.h>
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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 specific definitions. */
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#define LCD_CLEAR_DISPLAY_CMD 0x01
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#define LCD_CURSOR_HOME_CMD 0x02
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#define LCD_ENTRY_MODE_CMD 0x04
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#define LCD_ENTRY_MODE_INCREASE 0x02
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#define LCD_DISPLAY_CTRL_CMD 0x08
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#define LCD_DISPLAY_CTRL_DISPLAY_ON 0x04
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#define LCD_FUNCTION_SET_CMD 0x20
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#define LCD_FUNCTION_SET_8_BITS 0x10
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#define LCD_FUNCTION_SET_2_LINES 0x08
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#define LCD_FUNCTION_SET_LRG_FONT 0x04
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#define LCD_NEW_LINE 0xC0
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#define LCD_COMMAND_ADDRESS 0x00
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#define LCD_DATA_ADDRESS 0x01
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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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/* LCD access functions. */
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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( LCD_CURSOR_HOME_CMD );
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}
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else
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{
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prvLCDCommand( LCD_NEW_LINE );
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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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PMPSetAddress( LCD_COMMAND_ADDRESS );
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PMPMasterWrite( cCommand );
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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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PMPSetAddress( LCD_DATA_ADDRESS );
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PMPMasterWrite( cChar );
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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(LCD_CLEAR_DISPLAY_CMD);
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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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/* Open the PMP port */
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mPMPOpen((PMP_ON | PMP_READ_WRITE_EN | PMP_CS2_CS1_EN |
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PMP_LATCH_POL_HI | PMP_CS2_POL_HI | PMP_CS1_POL_HI |
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PMP_WRITE_POL_HI | PMP_READ_POL_HI),
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(PMP_MODE_MASTER1 | PMP_WAIT_BEG_4 | PMP_WAIT_MID_15 |
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PMP_WAIT_END_4),
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PMP_PEN_0, 0);
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/* Wait for the LCD to power up correctly. */
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vTaskDelay( lcdLONG_DELAY );
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vTaskDelay( lcdLONG_DELAY );
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vTaskDelay( lcdLONG_DELAY );
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/* Set up the LCD function. */
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prvLCDCommand( LCD_FUNCTION_SET_CMD | LCD_FUNCTION_SET_8_BITS | LCD_FUNCTION_SET_2_LINES | LCD_FUNCTION_SET_LRG_FONT );
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/* Turn the display on. */
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prvLCDCommand( LCD_DISPLAY_CTRL_CMD | LCD_DISPLAY_CTRL_DISPLAY_ON );
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/* Clear the display. */
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prvLCDCommand( LCD_CLEAR_DISPLAY_CMD );
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vTaskDelay( lcdLONG_DELAY );
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/* Increase the cursor. */
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prvLCDCommand( LCD_ENTRY_MODE_CMD | LCD_ENTRY_MODE_INCREASE );
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vTaskDelay( lcdLONG_DELAY );
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vTaskDelay( lcdLONG_DELAY );
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vTaskDelay( lcdLONG_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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