FreeRTOS-Kernel/Demo/CORTEX_LM3S102_Rowley/Demo3/main.c

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/*
 * This is a mini co-routine demo for the Rowley CrossFire LM3S102 development
 * board.  It makes use of the boards tri-colour LED and analogue input.
 *
 * Four co-routines are created - an 'I2C' co-routine and three 'flash'
 * co-routines.
 *
 * The I2C co-routine triggers an ADC conversion then blocks on a queue to 
 * wait for the conversion result - which it receives on the queue directly
 * from the I2C interrupt service routine.  The conversion result is then
 * scalled to a delay period.  The I2C interrupt then wakes each of the 
 * flash co-routines before itself delaying for the calculated period and
 * then repeating the whole process.
 *
 * When woken by the I2C co-routine the flash co-routines each block for 
 * a given period, illuminate an LED for a fixed period, then go back to
 * sleep to wait for the next cycle.  The uxIndex parameter of the flash
 * co-routines is used to ensure that each flashes a different LED, and that
 * the delay periods are such that the LED's get flashed in sequence.
 */


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

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

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

/* States of the I2C master interface. */
#define mainI2C_IDLE       0
#define mainI2C_READ_1     1
#define mainI2C_READ_2     2
#define mainI2C_READ_DONE  3

#define mainZERO_LENGTH 0

/* Address of the A2D IC on the CrossFire board. */
#define mainI2CAddress	0x4D

/* The queue used to send data from the I2C ISR to the co-routine should never
contain more than one item as the same co-routine is used to trigger the I2C
activity. */
#define mainQUEUE_LENGTH 1

/* The CrossFire board contains a tri-colour LED. */
#define mainNUM_LEDs	3

/* The I2C co-routine has a higher priority than the flash co-routines.  This
is not really necessary as when the I2C co-routine is active the other 
co-routines are delaying. */
#define mainI2c_CO_ROUTINE_PRIORITY 1


/* The current state of the I2C master. */
static volatile unsigned portBASE_TYPE uxState = mainI2C_IDLE;

/* The delay period derived from the A2D value. */
static volatile portBASE_TYPE uxDelay = 250;

/* The queue used to communicate between the I2C interrupt and the I2C 
co-routine. */
static xQueueHandle xADCQueue;

/* The queue used to synchronise the flash co-routines. */
static xQueueHandle xDelayQueue;

/*
 * Sets up the PLL, I2C and GPIO used by the demo.
 */
static void prvSetupHardware( void );

/* The co-routines as described at the top of the file. */
static void vI2CCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
static void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );

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

int main( void )
{
unsigned portBASE_TYPE uxCoRoutine;

	/* Setup all the hardware used by this demo. */
	prvSetupHardware();

	/* Create the queue used to communicate between the ISR and I2C co-routine.
	This can only ever contain one value. */
	xADCQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( portTickType ) );

	/* Create the queue used to synchronise the flash co-routines.  The queue
	is used to trigger three tasks, but is for synchronisation only and does
	not pass any data.  It therefore has three position each of zero length. */
	xDelayQueue = xQueueCreate( mainNUM_LEDs, mainZERO_LENGTH );

	/* Create the co-routine that initiates the i2c. */
	xCoRoutineCreate( vI2CCoRoutine, mainI2c_CO_ROUTINE_PRIORITY, 0 );

	/* Create the flash co-routines. */
	for( uxCoRoutine = 0; uxCoRoutine < mainNUM_LEDs; uxCoRoutine++ )
	{
		xCoRoutineCreate( vFlashCoRoutine, tskIDLE_PRIORITY, uxCoRoutine );        
	}

	/* Start the scheduler.  From this point on the co-routines should 
	execute. */
	vTaskStartScheduler();

	/* Should not get here unless we did not have enough memory to start the
	scheduler. */
	for( ;; );
	return 0;
}
/*-----------------------------------------------------------*/

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

	/* Enable the I2C used to read the pot. */
	SysCtlPeripheralEnable( SYSCTL_PERIPH_I2C );
	SysCtlPeripheralEnable( SYSCTL_PERIPH_GPIOB );
	GPIOPinTypeI2C( GPIO_PORTB_BASE, GPIO_PIN_2 | GPIO_PIN_3 );

	/* Initialize the I2C master. */
	I2CMasterInit( I2C_MASTER_BASE, pdFALSE );
	
	/* Enable the I2C master interrupt. */
	I2CMasterIntEnable( I2C_MASTER_BASE );
    IntEnable( INT_I2C );

	/* Initialise the hardware used to talk to the LED's. */
	vParTestInitialise();
}
/*-----------------------------------------------------------*/

static void vI2CCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
portTickType xADCResult;
static portBASE_TYPE xResult = 0, xMilliSecs, xLED;

	crSTART( xHandle );

	for( ;; )
	{
		/* Start the I2C off to read the ADC. */
		uxState = mainI2C_READ_1;
		I2CMasterSlaveAddrSet( I2C_MASTER_BASE, mainI2CAddress, pdTRUE );		
		I2CMasterControl( I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_START );

		/* Wait to receive the conversion result. */
		crQUEUE_RECEIVE( xHandle, xADCQueue, &xADCResult, portMAX_DELAY, &xResult );

		/* Scale the result to give a useful range of values for a visual 
		demo. */
		xADCResult >>= 2;
		xMilliSecs = xADCResult / portTICK_RATE_MS;

		/* The delay is split between the four co-routines so they remain in
		synch. */
		uxDelay = xMilliSecs / ( mainNUM_LEDs + 1 );

		/* Trigger each of the flash co-routines. */
		for( xLED = 0; xLED < mainNUM_LEDs; xLED++ )
		{
			crQUEUE_SEND( xHandle, xDelayQueue, &xLED, 0, &xResult );
		}

		/* Wait for the full delay time then start again.  This delay is long 
		enough to ensure the flash co-routines have done their thing and gone
		back to sleep. */
		crDELAY( xHandle, xMilliSecs );
	}

	crEND();
}
/*-----------------------------------------------------------*/

static void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
portBASE_TYPE xResult, xNothing;

	crSTART( xHandle );

	for( ;; )
	{
		/* Wait for start of next round. */
		crQUEUE_RECEIVE( xHandle, xDelayQueue, &xNothing, portMAX_DELAY, &xResult );

		/* Wait until it is this co-routines turn to flash. */
		crDELAY( xHandle, uxDelay * uxIndex );

		/* Turn on the LED for a fixed period. */
		vParTestSetLED( uxIndex, pdTRUE );
		crDELAY( xHandle, uxDelay );
		vParTestSetLED( uxIndex, pdFALSE );

		/* Go back and wait for the next round. */
	}

	crEND();
}
/*-----------------------------------------------------------*/

void vI2C_ISR(void)
{
static portTickType xReading;

	/* Clear the interrupt. */
	I2CMasterIntClear( I2C_MASTER_BASE );

	/* Determine what to do based on the current uxState. */
	switch (uxState)
	{
		case mainI2C_IDLE:		break;
	
		case mainI2C_READ_1:	/* Read ADC result high byte. */
								xReading = I2CMasterDataGet( I2C_MASTER_BASE );
								xReading <<= 8;
		
								/* Continue the burst read. */
								I2CMasterControl( I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_CONT );
								uxState = mainI2C_READ_2;
								break;
	
		case mainI2C_READ_2:	/* Read ADC result low byte. */
								xReading |= I2CMasterDataGet( I2C_MASTER_BASE );								
			
								/* Finish the burst read. */
								I2CMasterControl( I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_FINISH );
								uxState = mainI2C_READ_DONE;
								break;
			
		case mainI2C_READ_DONE:	/* Complete. */
								I2CMasterDataGet( I2C_MASTER_BASE );
								uxState = mainI2C_IDLE;

								/* Send the result to the co-routine. */
                                crQUEUE_SEND_FROM_ISR( xADCQueue, &xReading, pdFALSE );
								break;
	}
}
/*-----------------------------------------------------------*/

void vApplicationIdleHook( void )
{
	for( ;; )
	{
		vCoRoutineSchedule();
	}
}