/* | |
FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd. | |
FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT | |
http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. | |
*************************************************************************** | |
* * | |
* FreeRTOS tutorial books are available in pdf and paperback. * | |
* Complete, revised, and edited pdf reference manuals are also * | |
* available. * | |
* * | |
* Purchasing FreeRTOS documentation will not only help you, by * | |
* ensuring you get running as quickly as possible and with an * | |
* in-depth knowledge of how to use FreeRTOS, it will also help * | |
* the FreeRTOS project to continue with its mission of providing * | |
* professional grade, cross platform, de facto standard solutions * | |
* for microcontrollers - completely free of charge! * | |
* * | |
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
* * | |
* Thank you for using FreeRTOS, and thank you for your support! * | |
* * | |
*************************************************************************** | |
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. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
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, training, latest versions, license | |
and contact details. | |
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, | |
including FreeRTOS+Trace - an indispensable productivity tool. | |
Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell | |
the code with commercial support, indemnification, and middleware, under | |
the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also | |
provide a safety engineered and independently SIL3 certified version under | |
the SafeRTOS brand: http://www.SafeRTOS.com. | |
*/ | |
/* 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 ); | |
} | |
} | |