spi.c

AVR单片机的电机测速程序

#include "includes.h"

void Spi_Init(void)
{
 SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);; //setup SPI
 SPSR = 0x00; //setup SPI
}
void Spi_Byte_Tx(unsigned char cdata)
{
SPDR=cdata;
while(!(SPSR&(1<<SPIF)))
{}
}
void Spi_Port_Init(void)
{
DDRB  = 0xFF;
PORTB = 0xff;//PB4=1,AVR为主机，且MOSI输出
}