spidriver.c

uboot底层驱动

#include "hardware_reg.h"
#define SPI_CS_H()	do{*(unsigned long *)PORTD_DATA |= 0X8;}while(0);
#define SPI_CS_L()	do{*(unsigned long *)PORTD_DATA &= ~0X8;}while(0);
void NOP()
{
	int i;
	for(i=0;i<1;i++);
}

void init_SPI(void)
{
	/* 3?ê??ˉPD3?aê?3?￡?×÷?aAD7927μ?CS?? */
	*(unsigned long *)PORTD_DIR &= ~0x8;
	*(unsigned long *)PORTD_SEL |= 0x8;
	*(unsigned long *)PORTD_DATA |= 0X8;
	
	/* ????SPI?￡?é */
	*(unsigned long *)SPICR |= 0x6f;	//2?ê1?üSPI,μúò??????μ??óDD§￡?16??êy?Y
	*(unsigned long *)SPIBR = 0x0000;		//BaudRateDivisor?a4
	
}

/* ·μ???óê??μ￡?command?üá? */
unsigned short SPI_Transfer(unsigned short command)
{
	unsigned short data, i;

    /* set the command through the spi that let AD exchange data */     
	*(unsigned long *)SPITR = command;
	SPI_CS_L();
	NOP();
	*(unsigned long *)SPICR |= 0x80;
	NOP();
	while(!(( (*(volatile unsigned long *)SPISR)) & 0x01));// wait for the data from spi
	NOP();
	SPI_CS_H();
	NOP();
	data = *(unsigned long *)SPIRR; 

	return data;
}