spi_slave.c

AVR的SPI的通信例子

#include "SPI_Slave.h"


void  SPIInit(void)
{
  volatile INT8U  temp;
  DDRB |= (1<<MISO);
  DDRB &=~((1<<MOSI)|(1<<SS)|(1<<SCK));
  PORTB&=~(1<<MISO);
  SPCR  = 1<<SPE;                           //SPI允许，MSB，不允许SPI中断，极性方式00，1/2系统时钟速率
  SPSR  = 1<<SPI2X;
  temp  = SPSR;
  temp  = SPDR;                            //清空SPI，和中断标志，使SPI空闲
}

void SPIPutChar(INT8U data)
{
  SPDR=data;
}

INT8U SPIGetChar(void)
{
  INT8U data;
  data=SPDR;
  while(!(SPSR&(1<<SPIF)));
  data=SPDR;
  data=SPDR;
  return data;
}
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