Program to use the SPI in master mode

#include 

main()
{
	/****************************************************************
	 * SPI Setup
	*****************************************************************/
	DDRS = DDRS | 0xE0;  /* SS, SCLK, MOSI outputs */

	PORTS = PORTS | 0x80;  /* Bring SS high to deselect slave */

	SP0CR1 = 0x50;  /* 0 1 0 1 0 0 0 0                          
                       | | | | | | | |
                       | | | | | | | \____ MSB first
                       | | | | | | \______ multiple bytes with SS asserted
                       | | | | | \________ 0 phase
                       | | | | \__________ 0 polarity
                       | | | \____________ Master mode
                       | | \______________ not open drain
                       | \________________ Enable SPI
                       \__________________ No interrupts      
					*/

	SP0CR2 = 0;     /* Normal (not bi-directional) mode */
	SP0BR = 0x02;   /* 1 MHz SPI clock */
	/****************************************************************
	 * End of SPI Setup
	****************************************************************/

	PORTS = PORTS & ~0x80;         /* Bring SS low to select slave */

	SP0DR = 'h';                   /* Send 'h' */
	while ((SP0SR & 0x80) == 0) ;  /* Wait for transfer to finish */

	SP0DR = 'e';                   /* Send 'e' */
	while ((SP0SR & 0x80) == 0) ;  /* Wait for transfer to finish */

	SP0DR = 'l';                   /* Send 'l' */
	while ((SP0SR & 0x80) == 0) ;  /* Wait for transfer to finish */

	SP0DR = 'l';                   /* Send 'l' */
	while ((SP0SR & 0x80) == 0) ;  /* Wait for transfer to finish */

	SP0DR = 'o';                   /* Send 'o' */
	while ((SP0SR & 0x80) == 0) ;  /* Wait for transfer to finish */

	PORTS = PORTS | 0x80;          /* Bring SS high to deselect slave */
}