spi.c

来自「AVR下的ICC所有函数库代码」· C语言 代码 · 共 43 行

#include <io8515.h>	// change to the appropriate header file
#include "spi.h"


/* spi_init function should be generated using the AppBuilder
 */

/*
**  SpiWriteByte() writes a byte to the SPI and waits until
**  it has been transmitted. This function doesn't
**  return any value back.
*/
void SpiWriteByte(unsigned char byte)
{
    SPDR = byte;
    while (!(SPSR & 0x80));
    byte = SPDR;
}

/*
**  SpiReadByte() first writes a byte (a dummy, since
**  that byte is to generate clock signals to "poll" home
**  the byte from the slave. The function returns the
**  received byte.
*/
unsigned char SpiReadByte(void)
{
    SPDR = 0x00;
    while (!(SPSR & 0x80));
    return SPDR;
}

/*
**  SpiReadDataReg() reads the last byte in the SPI register
**  without any clock signals generated. Could be used
**  as reading the last byte received.
*/
unsigned char SpiReadDataReg(void)
{
    return SPDR;
}