Atmel Studio入門：SPI

//SPI Master Sample Code
//Target Device: ATmega328p
//Author: easy labo
//Created: 2014.11.02

#include <avr/io.h>

void InitSpiMaster(void)
{
   //Set MOSI(PB3) and SCK(PB5) output, all others input in Port B
   DDRB = (1<<DDB3)|(1<<DDB5);
   //Enable SPI, Master, set clock rate fck/16
   SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);
   //Double SPI Speed
   //SPSR |= _BV(SPI2X);
}

void TransSpiMaster(char tData){
   //Start transmission
   SPDR = tData;
   // Wait for transmission complete
   while(!(SPSR & (1<<SPIF)));
}

char RecieveSpiMaster(void)
{
   char rData;
   //Output Clolk without data
   SPDR = 0;
   // Wait for transmission complete
   while(!(SPSR & (1<<SPIF)));
   //Recieve 1 byte data
   rData = SPDR;
   return rData;
}

char TransceiverSpiMaster(char tData)
{
   char rData;
   //Start transmission
   SPDR = tData;
   // Wait for transmission complete
   while(!(SPSR & (1<<SPIF)));
   //Recieve 1 byte data
   rData = SPDR;
   return rData;
}