FreeRTOS/Demo/dsPIC_MPLAB/lcd.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V8.2.3 - Copyright (C) 2015 Real Time Engineers Ltd.
     All rights reserved

     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

     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 on the following
     link: http://www.freertos.org/a00114.html

     ***************************************************************************
      *                                                                       *
      *    FreeRTOS provides completely free yet professionally developed,    *
      *    robust, strictly quality controlled, supported, and cross          *
      *    platform software that is more than just the market leader, it     *
      *    is the industry's de facto standard.                               *
      *                                                                       *
      *    Help yourself get started quickly while simultaneously helping     *
      *    to support the FreeRTOS project by purchasing a FreeRTOS           *
      *    tutorial book, reference manual, or both:                          *
      *    http://www.FreeRTOS.org/Documentation                              *
      *                                                                       *
     ***************************************************************************

     http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
     the FAQ page "My application does not run, what could be wrong?".  Have you
     defined configASSERT()?

     http://www.FreeRTOS.org/support - In return for receiving this top quality
     embedded software for free we request you assist our global community by
     participating in the support forum.

     http://www.FreeRTOS.org/training - Investing in training allows your team to
     be as productive as possible as early as possible.  Now you can receive
     FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
     Ltd, and the world's leading authority on the world's leading RTOS.

     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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
     Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

     http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
     Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
     licenses offer ticketed support, indemnification and commercial 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 short usRow );

 /*
  * Write a string of text to the LCD.
  */
 static void prvLCDPutString( char *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_PERIOD_MS )
 #define lcdLONG_DELAY		( 15 / portTICK_PERIOD_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. */
 QueueHandle_t xLCDQueue;

 static void prvLCDCommand( char cCommand );
 static void prvLCDData( char cChar );

 /*-----------------------------------------------------------*/

 QueueHandle_t 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, "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );

 	return xLCDQueue;
 }
 /*-----------------------------------------------------------*/

 static void prvLCDGotoRow( unsigned short usRow )
 {
 	if( usRow == 0 )
 	{
 		prvLCDCommand( lcdHOME );
 	}
 	else
 	{
 		prvLCDCommand( lcdLINE2 );
 	}
 }
 /*-----------------------------------------------------------*/

 static void prvLCDCommand( char 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( char 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( char *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 short 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 );
 	}
 }
	/*
	FreeRTOS V8.2.3 - Copyright (C) 2015 Real Time Engineers Ltd.
	All rights reserved

	VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

	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 on the following
	link: http://www.freertos.org/a00114.html

	***************************************************************************
	* *
	* FreeRTOS provides completely free yet professionally developed, *
	* robust, strictly quality controlled, supported, and cross *
	* platform software that is more than just the market leader, it *
	* is the industry's de facto standard. *
	* *
	* Help yourself get started quickly while simultaneously helping *
	* to support the FreeRTOS project by purchasing a FreeRTOS *
	* tutorial book, reference manual, or both: *
	* http://www.FreeRTOS.org/Documentation *
	* *
	***************************************************************************

	http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
	the FAQ page "My application does not run, what could be wrong?". Have you
	defined configASSERT()?

	http://www.FreeRTOS.org/support - In return for receiving this top quality
	embedded software for free we request you assist our global community by
	participating in the support forum.

	http://www.FreeRTOS.org/training - Investing in training allows your team to
	be as productive as possible as early as possible. Now you can receive
	FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
	Ltd, and the world's leading authority on the world's leading RTOS.

	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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
	Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

	http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
	Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
	licenses offer ticketed support, indemnification and commercial 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 short usRow );

	/*
	* Write a string of text to the LCD.
	*/
	static void prvLCDPutString( char *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_PERIOD_MS )
	#define lcdLONG_DELAY ( 15 / portTICK_PERIOD_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. */
	QueueHandle_t xLCDQueue;

	static void prvLCDCommand( char cCommand );
	static void prvLCDData( char cChar );

	/-----------------------------------------------------------/

	QueueHandle_t 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, "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );

	return xLCDQueue;
	}
	/-----------------------------------------------------------/

	static void prvLCDGotoRow( unsigned short usRow )
	{
	if( usRow == 0 )
	{
	prvLCDCommand( lcdHOME );
	}
	else
	{
	prvLCDCommand( lcdLINE2 );
	}
	}
	/-----------------------------------------------------------/

	static void prvLCDCommand( char 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( char 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( char *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 short 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 );
	}
	}