main.c

FreeRTOSV4.1.0 安裝文件 FreeRTOS 是一个源码公开的免费的嵌入式实时操作系统

/*
	FreeRTOS.org V4.1.0 - Copyright (C) 2003-2006 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 six co-routines and two tasks (three including 
 * the idle task).  The co-routines execute as part of the idle task hook.
 *
 * Five 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' rotates a string on the LCD, delaying between each character
 * as necessitated by the slow interface, and delaying between each string just
 * long enough to enable the text to be read.
 *
 * The sixth 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 repetative calls to 
 * prvSetAndCheckRegisters().  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 
 * mechansim.
 *
 */

/* 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"

/* 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 )

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

/* The length of the queue used to pass received characters to the Comms Rx
task. */
#define mainRX_QUEUE_LEN			( 5 )

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

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

/* The time between transmissions of the string on UART 0.   This is pseudo
random in order to generate a bit or randomness to when the interrupts occur.*/
#define mainMIN_TX_DELAY			( 40 / portTICK_RATE_MS )
#define mainMAX_TX_DELAY			( ( portTickType ) 0x7f )
#define mainOFFSET_TIME				( ( portTickType ) 3 )

/* The time the Comms Rx task should wait to receive a character.  This should
be slightly longer than the time between transmissions.  If we do not receive
a character after this time then there must be an error in the transmission or
the timing of the transmission. */
#define mainCOMMS_RX_DELAY			( mainMAX_TX_DELAY + 20 )

/* The task priorites. */
#define mainLCD_TASK_PRIORITY		( tskIDLE_PRIORITY )
#define mainCOMMS_RX_TASK_PRIORITY	( tskIDLE_PRIORITY + 1 )

/* The LED's toggled by the various tasks. */
#define mainCOMMS_FAIL_LED			( 7 )
#define mainCOMMS_RX_LED			( 6 )
#define mainCOMMS_TX_LED			( 5 )

/* The baud rate used by the UART comms tasks/co-routine. */
#define mainBAUD_RATE				( 57600 )

/* FIFO setting for the UART.  The FIFO is not used to create a better test. */
#define mainFIFO_SET				( 0x10 )

/* The string that is transmitted on the UART contains sequentially the 
characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */
#define mainFIRST_TX_CHAR '0'
#define mainLAST_TX_CHAR 'z'

/* Just used to walk through the program memory in order that some random data
can be generated. */
#define mainTOTAL_PROGRAM_MEMORY ( ( unsigned portLONG * ) ( 8 * 1024 ) )
#define mainFIRST_PROGRAM_BYTES ( ( unsigned portLONG * ) 4 )

/* The error routine that is called if the driver library encounters an error. */
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

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

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

/*
 * The task that receives the characters from UART 0.
 */
static void vCommsRxTask( void * pvParameters );

/*
 * The co-routine that periodically initiates the transmission of the string on
 * the UART.
 */
static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );

/* 
 * Writes a string the the LCD.
 */
static void prvWriteString( const portCHAR *pcString );

/*
 * Initialisation routine for the UART.
 */
static void vSerialInit( void );

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

/*
 * 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.
 */
void prvSetAndCheckRegisters( void );

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

/*
 * Sets up the PLL and ports used by the demo.
 */
static void prvSetupHardware( void );

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

/* 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 next character to transmit. */
static portCHAR cNextChar;

/* The queue used to transmit characters from the interrupt to the Comms Rx
task. */
static xQueueHandle xCommsQueue;

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

void Main( void )
{
	/* Create the queue used to communicate between the UART ISR and the Comms
	Rx task. */
	xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( portCHAR ) );

	/* 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. */
	xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );

	/* Create the LCD and Comms Rx tasks. */
	xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );
	xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );

	/* Start the scheduler running the tasks and co-routines just created. */
	vTaskStartScheduler();

	/* Should not get here unless we did not have enough memory to start the
	scheduler. */
	for( ;; );
}
/*-----------------------------------------------------------*/

static void prvSetupHardware( void )
{
	/* Setup the PLL. */
	SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );

	/* Initialise the hardware used to talk to the LCD, LED's and UART. */
	PDCInit();
	vParTestInitialise();
	vSerialInit();
}
/*-----------------------------------------------------------*/

void vApplicationIdleHook( void )
{
	/* The co-routines are executed in the idle task using the idle task 
	hook. */
	for( ;; )
	{
		/* Schedule the co-routines. */
		vCoRoutineSchedule();

		/* Run the register check function between each co-routine. */
		prvSetAndCheckRegisters();
	}
}
/*-----------------------------------------------------------*/

static void prvWriteString( const portCHAR *pcString )
{
	/* Write pcString to the LED, pausing between each character. */
	prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);        
	while( *pcString )
	{
		vTaskDelay( mainCHAR_WRITE_DELAY );
		prvPDCWrite( PDC_LCD_RAM, *pcString );
		pcString++;
	}
}
/*-----------------------------------------------------------*/

void vLCDTask( void * pvParameters )
{
unsigned portBASE_TYPE uxIndex;
const unsigned portCHAR ucCFGData[] = {	
											0x30,   /* Set data bus to 8-bits. */
											0x30,
											0x30,
											0x3C,   /* Number of lines/font. */
											0x08,   /* Display off. */
											0x01,   /* Display clear. */
											0x06,   /* Entry mode [cursor dir][shift]. */
											0x0C	/* Display on [display on][curson on][blinking on]. */
									  };  

/* The strings that are written to the LCD. */
const portCHAR *pcStringsToDisplay[] = {										
											"Stellaris",