.equ	MOSI = 3		;for ATmega328
.equ	SCK = 5
.equ	SS = 2
	     
	LDI	R17,0xFF		;Port D is output
	OUT	DDRD,R17

	LDI 	R17,(1<<MOSI)|(1<<SCK)|(1<<SS)
	OUT 	DDRB,R17	;MOSI,SCK, and SS output 

	LDI 	R17,(1<<SPE)|(1<<MSTR)|(1<<SPR0)	;enable SPI
	OUT 	SPCR,R17	;master, CLK = fck/16	
Transmit:
	CBI 	PORTB,SS	;enable slave device
	LDI 	R17,'G'		;move G letter to R17
	OUT 	SPDR,R17	;start transmission of G
Wait:
	IN		R20,SPSR
	SBRS 	R20,SPIF	;wait for transmission
	RJMP 	Wait		;to complete
	IN		R18,SPDR	;read received data into R18
	OUT		PORTD,R18	;move R18 to PORTD

	SBI 	PORTB,SS	;disable slave device
	RJMP 	Transmit	;do it again