| /* | |
| FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd. | |
| All rights reserved | |
| VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. | |
| *************************************************************************** | |
| * * | |
| * FreeRTOS provides completely free yet professionally developed, * | |
| * robust, strictly quality controlled, supported, and cross * | |
| * platform software that has become a de facto standard. * | |
| * * | |
| * Help yourself get started quickly and support the FreeRTOS * | |
| * project by purchasing a FreeRTOS tutorial book, reference * | |
| * manual, or both from: http://www.FreeRTOS.org/Documentation * | |
| * * | |
| * Thank you! * | |
| * * | |
| *************************************************************************** | |
| This file is part of the FreeRTOS distribution. | |
| FreeRTOS is free software; you can redistribute it and/or modify it under | |
| the terms of the GNU General Public License (version 2) as published by the | |
| Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception. | |
| >>! NOTE: The modification to the GPL is included to allow you to distribute | |
| >>! a combined work that includes FreeRTOS without being obliged to provide | |
| >>! the source code for proprietary components outside of the FreeRTOS | |
| >>! kernel. | |
| FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY | |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
| FOR A PARTICULAR PURPOSE. Full license text is available from the following | |
| link: http://www.freertos.org/a00114.html | |
| 1 tab == 4 spaces! | |
| *************************************************************************** | |
| * * | |
| * Having a problem? Start by reading the FAQ "My application does * | |
| * not run, what could be wrong?" * | |
| * * | |
| * http://www.FreeRTOS.org/FAQHelp.html * | |
| * * | |
| *************************************************************************** | |
| http://www.FreeRTOS.org - Documentation, books, training, latest versions, | |
| license and Real Time Engineers Ltd. contact details. | |
| http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, | |
| including FreeRTOS+Trace - an indispensable productivity tool, a DOS | |
| compatible FAT file system, and our tiny thread aware UDP/IP stack. | |
| http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High | |
| Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS | |
| licenses offer ticketed support, indemnification and middleware. | |
| http://www.SafeRTOS.com - High Integrity Systems also provide a safety | |
| engineered and independently SIL3 certified version for use in safety and | |
| mission critical applications that require provable dependability. | |
| 1 tab == 4 spaces! | |
| */ | |
| /* Scheduler includes. */ | |
| #include "FreeRTOS.h" | |
| #include "task.h" | |
| #include "queue.h" | |
| /* Demo includes. */ | |
| #include "lcd.h" | |
| /* | |
| * The LCD is written to by more than one task so is controlled by this | |
| * 'gatekeeper' task. This is the only task that is actually permitted to | |
| * access the LCD directly. Other tasks wanting to display a message send | |
| * the message to the gatekeeper. | |
| */ | |
| static void vLCDTask( void *pvParameters ); | |
| /* | |
| * Setup the peripherals required to communicate with the LCD. | |
| */ | |
| static void prvSetupLCD( void ); | |
| /* | |
| * Move to the first (0) or second (1) row of the LCD. | |
| */ | |
| static void prvLCDGotoRow( unsigned portSHORT usRow ); | |
| /* | |
| * Write a string of text to the LCD. | |
| */ | |
| static void prvLCDPutString( portCHAR *pcString ); | |
| /* | |
| * Clear the LCD. | |
| */ | |
| static void prvLCDClear( void ); | |
| /*-----------------------------------------------------------*/ | |
| /* Brief delay to permit the LCD to catch up with commands. */ | |
| #define lcdVERY_SHORT_DELAY ( 1 ) | |
| #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS ) | |
| #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS ) | |
| /* LCD commands. */ | |
| #define lcdCLEAR ( 0x01 ) | |
| #define lcdHOME ( 0x02 ) | |
| #define lcdLINE2 ( 0xc0 ) | |
| /* SFR that seems to be missing from the standard header files. */ | |
| #define PMAEN *( ( unsigned short * ) 0x60c ) | |
| /* LCD R/W signal. */ | |
| #define lcdRW LATDbits.LATD5 | |
| /* LCD lcdRS signal. */ | |
| #define lcdRS LATBbits.LATB15 | |
| /* LCD lcdE signal . */ | |
| #define lcdE LATDbits.LATD4 | |
| /* Control signal pin direction. */ | |
| #define RW_TRIS TRISDbits.TRISD5 | |
| #define RS_TRIS TRISBbits.TRISB15 | |
| #define E_TRIS TRISDbits.TRISD4 | |
| /* Port for LCD data */ | |
| #define lcdDATA LATE | |
| #define lcdDATAPORT PORTE | |
| /* I/O setup for data Port. */ | |
| #define TRISDATA TRISE | |
| /* The length of the queue used to send messages to the LCD gatekeeper task. */ | |
| #define lcdQUEUE_SIZE 3 | |
| /*-----------------------------------------------------------*/ | |
| /* The queue used to send messages to the LCD task. */ | |
| xQueueHandle xLCDQueue; | |
| static void prvLCDCommand( portCHAR cCommand ); | |
| static void prvLCDData( portCHAR cChar ); | |
| /*-----------------------------------------------------------*/ | |
| xQueueHandle xStartLCDTask( void ) | |
| { | |
| /* Create the queue used by the LCD task. Messages for display on the LCD | |
| are received via this queue. */ | |
| xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ) ); | |
| /* Start the task that will write to the LCD. The LCD hardware is | |
| initialised from within the task itself so delays can be used. */ | |
| xTaskCreate( vLCDTask, ( signed portCHAR * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL ); | |
| return xLCDQueue; | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvLCDGotoRow( unsigned portSHORT usRow ) | |
| { | |
| if( usRow == 0 ) | |
| { | |
| prvLCDCommand( lcdHOME ); | |
| } | |
| else | |
| { | |
| prvLCDCommand( lcdLINE2 ); | |
| } | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvLCDCommand( portCHAR cCommand ) | |
| { | |
| /* Prepare RD0 - RD7. */ | |
| lcdDATA &= 0xFF00; | |
| /* Command byte to lcd. */ | |
| lcdDATA |= cCommand; | |
| /* Ensure lcdRW is 0. */ | |
| lcdRW = 0; | |
| lcdRS = 0; | |
| /* Toggle lcdE line. */ | |
| lcdE = 1; | |
| vTaskDelay( lcdVERY_SHORT_DELAY ); | |
| lcdE = 0; | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvLCDData( portCHAR cChar ) | |
| { | |
| /* ensure lcdRW is 0. */ | |
| lcdRW = 0; | |
| /* Assert register select to 1. */ | |
| lcdRS = 1; | |
| /* Prepare RD0 - RD7. */ | |
| lcdDATA &= 0xFF00; | |
| /* Data byte to lcd. */ | |
| lcdDATA |= cChar; | |
| lcdE = 1; | |
| Nop(); | |
| Nop(); | |
| Nop(); | |
| /* Toggle lcdE signal. */ | |
| lcdE = 0; | |
| /* Negate register select to 0. */ | |
| lcdRS = 0; | |
| vTaskDelay( lcdVERY_SHORT_DELAY ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvLCDPutString( portCHAR *pcString ) | |
| { | |
| /* Write out each character with appropriate delay between each. */ | |
| while( *pcString ) | |
| { | |
| prvLCDData( *pcString ); | |
| pcString++; | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| } | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvLCDClear( void ) | |
| { | |
| prvLCDCommand( lcdCLEAR ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void prvSetupLCD( void ) | |
| { | |
| /* Wait for proper power up. */ | |
| vTaskDelay( lcdLONG_DELAY ); | |
| /* Set initial states for the data and control pins */ | |
| LATE &= 0xFF00; | |
| /* R/W state set low. */ | |
| lcdRW = 0; | |
| /* lcdRS state set low. */ | |
| lcdRS = 0; | |
| /* lcdE state set low. */ | |
| lcdE = 0; | |
| /* Set data and control pins to outputs */ | |
| TRISE &= 0xFF00; | |
| /* lcdRW pin set as output. */ | |
| RW_TRIS = 0; | |
| /* lcdRS pin set as output. */ | |
| RS_TRIS = 0; | |
| /* lcdE pin set as output. */ | |
| E_TRIS = 0; | |
| /* 1st LCD initialization sequence */ | |
| lcdDATA &= 0xFF00; | |
| lcdDATA |= 0x0038; | |
| lcdE = 1; | |
| Nop(); | |
| Nop(); | |
| Nop(); | |
| /* Toggle lcdE signal. */ | |
| lcdE = 0; | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| /* 2nd LCD initialization sequence */ | |
| lcdDATA &= 0xFF00; | |
| lcdDATA |= 0x0038; | |
| lcdE = 1; | |
| Nop(); | |
| Nop(); | |
| Nop(); | |
| /* Toggle lcdE signal. */ | |
| lcdE = 0; | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| /* 3rd LCD initialization sequence */ | |
| lcdDATA &= 0xFF00; | |
| lcdDATA |= 0x0038; | |
| lcdE = 1; | |
| Nop(); | |
| Nop(); | |
| Nop(); | |
| /* Toggle lcdE signal. */ | |
| lcdE = 0; | |
| vTaskDelay( lcdSHORT_DELAY ); | |
| /* Function set. */ | |
| prvLCDCommand( 0x38 ); | |
| /* Display on/off control, cursor blink off (0x0C). */ | |
| prvLCDCommand( 0x0C ); | |
| /* Entry mode set (0x06). */ | |
| prvLCDCommand( 0x06 ); | |
| prvLCDCommand( lcdCLEAR ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| static void vLCDTask( void *pvParameters ) | |
| { | |
| xLCDMessage xMessage; | |
| unsigned portSHORT usRow = 0; | |
| /* Initialise the hardware. This uses delays so must not be called prior | |
| to the scheduler being started. */ | |
| prvSetupLCD(); | |
| /* Welcome message. */ | |
| prvLCDPutString( "www.FreeRTOS.org" ); | |
| for( ;; ) | |
| { | |
| /* Wait for a message to arrive that requires displaying. */ | |
| while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS ); | |
| /* Clear the current display value. */ | |
| prvLCDClear(); | |
| /* Switch rows each time so we can see that the display is still being | |
| updated. */ | |
| prvLCDGotoRow( usRow & 0x01 ); | |
| usRow++; | |
| prvLCDPutString( xMessage.pcMessage ); | |
| /* Delay the requested amount of time to ensure the text just written | |
| to the LCD is not overwritten. */ | |
| vTaskDelay( xMessage.xMinDisplayTime ); | |
| } | |
| } | |