main.c

开源实时操作系统

/*
	FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org 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
	along with FreeRTOS.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section 
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license 
	and contact details.  Please ensure to read the configuration and relevant 
	port sections of the online documentation.
	***************************************************************************
*/

/* 
 * This demo application creates eight co-routines and four tasks (five 
 * including the idle task).  The co-routines execute as part of the idle task 
 * hook.  The application is limited in size to allow its compilation using
 * the KickStart version of the IAR compiler.
 *
 * Six of the created co-routines are the standard 'co-routine flash' 
 * co-routines contained within the Demo/Common/Minimal/crflash.c file and 
 * documented on the FreeRTOS.org WEB site.  
 *
 * The 'LCD Task' waits on a message queue for messages informing it what and
 * where to display text.  This is the only task that accesses the LCD
 * so mutual exclusion is guaranteed.
 *
 * The 'LCD Message Task' periodically sends strings to the LCD Task using
 * the message queue.  The strings are rotated to form a short message and
 * are written to the top row of the LCD.
 *
 * The 'ADC Co-routine' periodically reads the ADC input that is connected to
 * the light sensor, forms a short message from the value, and then sends this
 * message to the LCD Task using the same message queue.  The ADC readings are
 * displayed on the bottom row of the LCD.  
 *
 * The eighth co-routine and final task control the transmission and reception
 * of a string to UART 0.  The co-routine periodically sends the first 
 * character of the string to the UART, with the UART's TxEnd interrupt being
 * used to transmit the remaining characters.  The UART's RxEnd interrupt 
 * receives the characters and places them on a queue to be processed by the 
 * 'COMs Rx' task.  An error is latched should an unexpected character be 
 * received, or any character be received out of sequence.  
 *
 * A loopback connector is required to ensure that each character transmitted 
 * on the UART is also received on the same UART.  For test purposes the UART
 * FIFO's are not utalised in order to maximise the interrupt overhead.  Also
 * a pseudo random interval is used between the start of each transmission in 
 * order that the resultant interrupts are more randomly distributed and 
 * therefore more likely to highlight any problems.
 *
 * The flash co-routines control LED's zero to four.  LED five is toggled each
 * time the string is transmitted on the UART.  LED six is toggled each time
 * the string is CORRECTLY received on the UART.  LED seven is latched on 
 * should an error be detected in any task or co-routine.
 *
 * In addition the idle task makes repetitive calls to 
 * vSetAndCheckRegisters().  This simply loads the general purpose registers 
 * with a known value, then checks each register to ensure the held value is 
 * still correct.  As a low priority task this checking routine is likely to 
 * get repeatedly swapped in and out.  A register being found to contain an 
 * incorrect value is therefore indicative of an error in the task switching 
 * mechanism.
 *
 */

/* standard include files. */
#include <stdio.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "croutine.h"

/* Demo application include files. */
#include "partest.h"
#include "crflash.h"
#include "commstest.h"

/* Library include files. */
#include "DriverLib.h"

/* The time to delay between writing each character to the LCD. */
#define mainCHAR_WRITE_DELAY		( 2 / portTICK_RATE_MS )

/* The time to delay between writing each string to the LCD. */
#define mainSTRING_WRITE_DELAY		( 400 / portTICK_RATE_MS )

#define mainADC_DELAY				( 200 / portTICK_RATE_MS )

/* The number of flash co-routines to create. */
#define mainNUM_FLASH_CO_ROUTINES	( 5 )

/* The length of the queue used to send messages to the LCD task. */
#define mainLCD_QUEUE_LEN			( 3 )

/* The priority of the co-routine used to initiate the transmission of the 
string on UART 0. */
#define mainTX_CO_ROUTINE_PRIORITY	( 1 )
#define mainADC_CO_ROUTINE_PRIORITY 	( 2 )

/* Only one of each co-routine is created so its index is not important. */
#define mainTX_CO_ROUTINE_INDEX		( 0 )
#define mainADC_CO_ROUTINE_INDEX  	( 0 )

/* The task priorities. */
#define mainLCD_TASK_PRIORITY		( tskIDLE_PRIORITY + 1 )
#define mainMSG_TASK_PRIORITY		( mainLCD_TASK_PRIORITY - 1 )
#define mainCOMMS_RX_TASK_PRIORITY	( tskIDLE_PRIORITY + 1 )

/* The LCD had two rows. */
#define mainTOP_ROW		0
#define mainBOTTOM_ROW 	1

/* Dimension for the buffer into which the ADC value string is written. */
#define mainMAX_ADC_STRING_LEN	20

/* The LED that is lit should an error be detected in any of the tasks or
co-routines. */
#define mainFAIL_LED			( 7 )

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

/*
 * The task that displays text on the LCD.
 */
static void prvLCDTask( void * pvParameters );

/*
 * The task that sends messages to be displayed on the top row of the LCD.
 */
static void prvLCDMessageTask( void * pvParameters );

/*
 * The co-routine that reads the ADC and sends messages for display on the
 * bottom row of the LCD.
 */
static void prvADCCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );

/*
 * Function to simply set a known value into the general purpose registers
 * then read them back to ensure they remain set correctly.  An incorrect value
 * being indicative of an error in the task switching mechanism.
 */
extern void vSetAndCheckRegisters( void );

/*
 * Latch the LED that indicates that an error has occurred. 
 */
void vSetErrorLED( void );

/*
 * Thread safe write to the PDC.
 */
static void prvPDCWrite( portCHAR cAddress, portCHAR cData );

/*
 * Sets up the hardware used by the demo.
 */
static void prvSetupHardware( void );


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

/* The structure that is passed on the LCD message queue. */
typedef struct
{
	portCHAR **ppcMessageToDisplay; /*<< Points to a char* pointing to the message to display. */
	portBASE_TYPE xRow;				/*<< The row on which the message should be displayed. */
} xLCDMessage;

/* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
defined within this file. */
unsigned portBASE_TYPE uxErrorStatus = pdPASS;

/* The queue used to transmit messages to the LCD task. */
static xQueueHandle xLCDQueue;

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

/*
 * Setup the hardware, create the tasks/co-routines, then start the scheduler.
 */
void main( void )
{
	/* Create the queue used by tasks wanting to write to the LCD. */
	xLCDQueue = xQueueCreate( mainLCD_QUEUE_LEN, sizeof( xLCDMessage ) );

	/* Setup the ports used by the demo and the clock. */
	prvSetupHardware();

	/* Create the co-routines that flash the LED's. */
	vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );

	/* Create the co-routine that initiates the transmission of characters
	on the UART and the task that receives them, as described at the top of
	this file. */
	xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
	xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );

	/* Create the task that waits for messages to display on the LCD, plus the
	task and co-routine that send messages for display (as described at the top
	of this file. */