#include <reg935.h>


// flag to indicate if SPI is currently involved in a transfer or not
// stops a write to the SPI bus while a write is in progress
static bit mspibusy;
unsigned char daten_send = 10;
unsigned char daten_empf;

sbit LED = 0xA0;

/***********************************************************************
DESC:    Writes a byte to the SPI bus. spi_init must be called first
RETURNS: Nothing
************************************************************************/
void spi_write (unsigned char dat)   // byte to write
{
	  // wait for previous transfer to complete
	  while (mspibusy);
	
	  // SPI now busy
	  mspibusy = 1;
	
	  // write data to SPI bus
	  SPDAT = dat;
} // spi_write



/***********************************************************************
DESC:    Writes a byte to the SPI bus and returns the byte
         received from the slave. spi_init must be called first
RETURNS: Byte received from slave
************************************************************************/
unsigned char spi_transfer( unsigned char dat  )    // byte to write
{
	  // wait for previous transfer to complete
	  while (mspibusy);
	
	  // SPI now busy
	  mspibusy = 1;
	
	  // write data to SPI bus
	  SPDAT = dat;
	
	  // wait for transfer to complete
	  while (mspibusy);
	
	  // return new data received
	  return SPDAT;
} // spi_transfer

/***********************************************************************
DESC:    SPI Interrupt Service Routine
         Called when byte transmitted and/or byte received
         or if mode changed to slave by Slave Select pin
RETURNS: Nothing
************************************************************************/
void spi_isr( void) interrupt 9 using 1
{
	  // clear SPIF bit by writing 1 to it

	  SPSTAT |= 0xFF; 
	
	  // SPI not busy
	  mspibusy = 0;
} // spi_isr

/***********************************************************************
DESC:    Initializes the SPI peripheral
         SPI Clock frequency = 93.75 kHz
         Set EA to 1 after calling
RETURNS: Nothing
************************************************************************/
void spi_init (void )
{
	  // set MOSI, MISO, /SS and SPICLK as quasi-bidirectional
	  P2M1 = 0;
	  P2M2 = 0;
	
	  // configure SPI
	  SPCTL = 0xD7;
	
	  // SPI initially not busy
	  mspibusy = 0;
	
	  // set SPI interrupt priority to 0
	  IP1 &= ~0x08;
	  IP1H &= ~0x08;
	
	  // enable SPI interrupt
	  ESPI = 1;
} // spi_init


void led () interrupt 2
{
	static unsigned	char i=0;
	if( i%2 == 0)
	{
		daten_send = 10;
		SPDAT = daten_send;

	}
	else
	{
		daten_send = 8;
		SPDAT = daten_send;

	}
	i++;
	
}


void main()
{

	spi_init();
	SPDAT = daten_send;
	
	EX1 = 1;
	IT1 = 1;
	EA=1;

	while(1)
	{
		
			    

	}
}