spi.c

实现了avr下对sd卡的读写,支持文件存取,删除的功能

//-------------------------------------------------------------------------
#include	<avr/io.h>
#include 	<stdint.h>


//-------------------------------------------------------------------------
#define	SS			PB4
#define	MOSI		PB5
#define	MISO		PB6
#define	SCK			PB7
//-------------------------------------------------------------------------
void spiInit(){
	DDRB|=(_BV(SS)|_BV(MOSI)|_BV(SCK));	
	SPCR=_BV(SPE)|_BV(MSTR);						// master mode
}
//-------------------------------------------------------------------------
uint8_t spiTransferByte(uint8_t data){
	SPDR=data;
	while((SPSR&_BV(SPIF))==0);
	return SPDR;
}
//-------------------------------------------------------------------------