FreeRTOS/Demo/PIC24_MPLAB/lcd.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V7.4.1 - Copyright (C) 2013 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 Real Time Engineers Ltd., 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, 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, and our new
     fully thread aware and reentrant UDP/IP stack.

     http://www.OpenRTOS.com - 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.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.
 */

 /* 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 lcdSHORT_DELAY		3

 /* SFR that seems to be missing from the standard header files. */
 #define PMAEN				*( ( unsigned short * ) 0x60c )

 /* LCD commands. */
 #define lcdDEFAULT_FUNCTION	0x3c
 #define lcdDISPLAY_CONTROL	0x0c
 #define lcdCLEAR_DISPLAY	0x01
 #define lcdENTRY_MODE		0x06

 /* 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;


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

 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 )
 	{
 		PMADDR = 0x0000;
 		PMDIN1 = 0x02;
 	}
 	else
 	{
 		PMADDR = 0x0000;
 		PMDIN1 = 0xc0;
 	}

 	vTaskDelay( lcdSHORT_DELAY );
 }
 /*-----------------------------------------------------------*/

 static void prvLCDPutString( portCHAR *pcString )
 {
 	/* Write out each character with appropriate delay between each. */
 	while( *pcString )
 	{
 		PMADDR = 0x0001;
 		PMDIN1 = *pcString;
 		pcString++;
 		vTaskDelay( lcdSHORT_DELAY );
 	}
 }
 /*-----------------------------------------------------------*/

 static void prvLCDClear( void )
 {
 	/* Clear the display. */
 	PMADDR = 0x0000;
 	PMDIN1 = lcdCLEAR_DISPLAY;
 	vTaskDelay( lcdSHORT_DELAY );
 }
 /*-----------------------------------------------------------*/

 static void prvSetupLCD( void )
 {
 	/* Setup the PMP. */
 	PMCON = 0x83BF;
 	PMMODE = 0x3FF;
 	PMAEN = 1;
 	PMADDR = 0x0000;
 	vTaskDelay( lcdSHORT_DELAY );

 	/* Set the default function. */
 	PMDIN1 = lcdDEFAULT_FUNCTION;
 	vTaskDelay( lcdSHORT_DELAY );

 	/* Set the display control. */
 	PMDIN1 = lcdDISPLAY_CONTROL;
 	vTaskDelay( lcdSHORT_DELAY );

 	/* Clear the display. */
 	PMDIN1 = lcdCLEAR_DISPLAY;
 	vTaskDelay( lcdSHORT_DELAY );

 	/* Set the entry mode. */
 	PMDIN1 = lcdENTRY_MODE;
 	vTaskDelay( lcdSHORT_DELAY );
 }
 /*-----------------------------------------------------------*/

 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 );
 	}
 }
	/*
	FreeRTOS V7.4.1 - Copyright (C) 2013 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 Real Time Engineers Ltd., 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, 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, and our new
	fully thread aware and reentrant UDP/IP stack.

	http://www.OpenRTOS.com - 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.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.
	*/

	/* 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 lcdSHORT_DELAY 3

	/* SFR that seems to be missing from the standard header files. */
	#define PMAEN ( ( unsigned short ) 0x60c )

	/* LCD commands. */
	#define lcdDEFAULT_FUNCTION 0x3c
	#define lcdDISPLAY_CONTROL 0x0c
	#define lcdCLEAR_DISPLAY 0x01
	#define lcdENTRY_MODE 0x06

	/* 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;


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

	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 )
	{
	PMADDR = 0x0000;
	PMDIN1 = 0x02;
	}
	else
	{
	PMADDR = 0x0000;
	PMDIN1 = 0xc0;
	}

	vTaskDelay( lcdSHORT_DELAY );
	}
	/-----------------------------------------------------------/

	static void prvLCDPutString( portCHAR *pcString )
	{
	/* Write out each character with appropriate delay between each. */
	while( *pcString )
	{
	PMADDR = 0x0001;
	PMDIN1 = *pcString;
	pcString++;
	vTaskDelay( lcdSHORT_DELAY );
	}
	}
	/-----------------------------------------------------------/

	static void prvLCDClear( void )
	{
	/* Clear the display. */
	PMADDR = 0x0000;
	PMDIN1 = lcdCLEAR_DISPLAY;
	vTaskDelay( lcdSHORT_DELAY );
	}
	/-----------------------------------------------------------/

	static void prvSetupLCD( void )
	{
	/* Setup the PMP. */
	PMCON = 0x83BF;
	PMMODE = 0x3FF;
	PMAEN = 1;
	PMADDR = 0x0000;
	vTaskDelay( lcdSHORT_DELAY );

	/* Set the default function. */
	PMDIN1 = lcdDEFAULT_FUNCTION;
	vTaskDelay( lcdSHORT_DELAY );

	/* Set the display control. */
	PMDIN1 = lcdDISPLAY_CONTROL;
	vTaskDelay( lcdSHORT_DELAY );

	/* Clear the display. */
	PMDIN1 = lcdCLEAR_DISPLAY;
	vTaskDelay( lcdSHORT_DELAY );

	/* Set the entry mode. */
	PMDIN1 = lcdENTRY_MODE;
	vTaskDelay( lcdSHORT_DELAY );
	}
	/-----------------------------------------------------------/

	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 );
	}
	}