main.c

开源实时操作系统

	xTaskCreate( prvLCDTask, "LCD", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainLCD_TASK_PRIORITY, NULL );
	xTaskCreate( prvLCDMessageTask, "MSG", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainMSG_TASK_PRIORITY, NULL );
	xCoRoutineCreate( prvADCCoRoutine, mainADC_CO_ROUTINE_PRIORITY, mainADC_CO_ROUTINE_INDEX );

	/* 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 prvLCDMessageTask( void * pvParameters )
{
/* The strings that are written to the LCD. */
portCHAR *pcStringsToDisplay[] = {										
									"IAR             ",
									"Stellaris       ",
									"Demo            ",
									"www.FreeRTOS.org",
									""
								};

xQueueHandle *pxLCDQueue;	
xLCDMessage xMessageToSend;
portBASE_TYPE xIndex = 0;

	/* To test the parameter passing mechanism, the queue on which messages are
	posted is passed in as a parameter even though it is available as a file
	scope variable anyway. */
	pxLCDQueue = ( xQueueHandle * ) pvParameters;

	for( ;; )
	{
		/* Wait until it is time to move onto the next string. */
		vTaskDelay( mainSTRING_WRITE_DELAY );		
		
		/* Create the message object to send to the LCD task. */
		xMessageToSend.ppcMessageToDisplay = &pcStringsToDisplay[ xIndex ];
		xMessageToSend.xRow = mainTOP_ROW;
		
		/* Post the message to be displayed. */
		if( !xQueueSend( *pxLCDQueue, ( void * ) &xMessageToSend, 0 ) )
		{
			uxErrorStatus = pdFAIL;
		}
		
		/* Move onto the next message, wrapping when necessary. */
		xIndex++;		
		if( *( pcStringsToDisplay[ xIndex ] ) == 0x00 )
		{
			xIndex = 0;

			/* Delay longer before going back to the start of the messages. */
			vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
		}
	}
}
/*-----------------------------------------------------------*/

void prvLCDTask( void * pvParameters )
{
unsigned portBASE_TYPE uxIndex;
xQueueHandle *pxLCDQueue;
xLCDMessage xReceivedMessage;
portCHAR *pcString;
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]. */
									  };  

	/* To test the parameter passing mechanism, the queue on which messages are
	received is passed in as a parameter even though it is available as a file
	scope variable anyway. */
	pxLCDQueue = ( xQueueHandle * ) pvParameters;

	/* Configure the LCD. */
	uxIndex = 0;
	while( uxIndex < sizeof( ucCFGData ) )
	{
		prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
		uxIndex++;
		vTaskDelay( mainCHAR_WRITE_DELAY );
	}

	/* Turn the LCD Backlight on. */
	prvPDCWrite( PDC_CSR, 0x01 );

	/* Clear display. */
	vTaskDelay( mainCHAR_WRITE_DELAY );
	prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR ); 

	uxIndex = 0;
	for( ;; )    
	{
		/* Wait for a message to arrive. */
		if( xQueueReceive( *pxLCDQueue, &xReceivedMessage, portMAX_DELAY ) )
		{
			/* Which row does the received message say to write to? */
			PDCLCDSetPos( 0, xReceivedMessage.xRow );

			/* Where is the string we are going to display? */
			pcString = *xReceivedMessage.ppcMessageToDisplay;
			
			while( *pcString )
			{
				/* Don't write out the string too quickly as LCD's are usually 
				pretty slow devices. */
				vTaskDelay( mainCHAR_WRITE_DELAY );
				prvPDCWrite( PDC_LCD_RAM, *pcString );
				pcString++;
			}		
		}
	}
}
/*-----------------------------------------------------------*/

static void prvADCCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
static unsigned portLONG ulADCValue;
static portCHAR cMessageBuffer[ mainMAX_ADC_STRING_LEN ];
static portCHAR *pcMessage;
static xLCDMessage xMessageToSend;

	/* Co-routines MUST start with a call to crSTART(). */
	crSTART( xHandle );
	
	for( ;; )
	{
		/* Start an ADC conversion. */
		ADCProcessorTrigger( ADC_BASE, 0 );
		
		/* Simply delay - when we unblock the result should be available */	
		crDELAY( xHandle, mainADC_DELAY );
		
		/* Get the ADC result. */
		ADCSequenceDataGet( ADC_BASE, 0, &ulADCValue );

		/* Create a string with the result. */		
		sprintf( cMessageBuffer, "ADC = %d   ", ulADCValue );
		pcMessage = cMessageBuffer;

		/* Configure the message we are going to send for display. */
		xMessageToSend.ppcMessageToDisplay = ( portCHAR** ) &pcMessage;
		xMessageToSend.xRow = mainBOTTOM_ROW;
		
		/* Send the string to the LCD task for display.  We are sending
		on a task queue so do not have the option to block. */
		if( !xQueueSend( xLCDQueue, ( void * ) &xMessageToSend, 0 ) )
		{
			uxErrorStatus = pdFAIL;
		}		
	}
	
	/* Co-routines MUST end with a call to crEND(). */
	crEND();
}
/*-----------------------------------------------------------*/

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();

	/* The ADC is used to read the light sensor. */
	SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC );
    ADCSequenceConfigure( ADC_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
    ADCSequenceStepConfigure( ADC_BASE, 0, 0, ADC_CTL_CH0 | ADC_CTL_END );
    ADCSequenceEnable( ADC_BASE, 0 );

}
/*-----------------------------------------------------------*/

static void prvPDCWrite( portCHAR cAddress, portCHAR cData )
{
	vTaskSuspendAll();
	{
		PDCWrite( cAddress, cData );
	}
	xTaskResumeAll();
}
/*-----------------------------------------------------------*/

void vSetErrorLED( void )
{
	vParTestSetLED( mainFAIL_LED, pdTRUE );
}
/*-----------------------------------------------------------*/

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. */
		vSetAndCheckRegisters();
		
		/* See if the comms task and co-routine has found any errors. */
		if( uxGetCommsStatus() != pdPASS )
		{
			vParTestSetLED( mainFAIL_LED, pdTRUE );
		}
	}
}
/*-----------------------------------------------------------*/