24c01.h

ic卡控制器24c01在软核处理器nios上的底层驱动程序

#include "excalibur.h"

np_pio* ic_scl=na_i2c_clk;
np_pio* ic_sda=na_i2c_dio;

void delayic(int n)
{
	int i;
	for(i=0;i<n;i++);	
}

void ic_start()
{
	ic_sda->np_piodata=1;
	ic_scl->np_piodata=1;
	ic_sda->np_piodata=0;
}

void ic_stop()
{
	ic_sda->np_piodata=0;
	ic_scl->np_piodata=1;
	ic_sda->np_piodata=1;	
}

void ic_ack()
{
	ic_scl->np_piodata=0;	
	ic_sda->np_piodata=0;
    ic_scl->np_piodata=1;
	delayic(1);  
	ic_scl->np_piodata=0;	
}   

void shift8(unsigned char a)//送指令
{
	unsigned char i;
	for(i=0;i<8;i++)
	{
		delayic(1);
		ic_scl->np_piodata=0;
		ic_sda->np_piodata=a>>7;
		a=a<<1;
		delayic(1);
		ic_scl->np_piodata=1;	
	}
	ic_ack();
}

unsigned char rd_24c01(unsigned char a)//读取数据，a为地址
{
	unsigned char i,d=0;
	ic_start();
	shift8(0xa0);
	shift8(a);
	ic_start();
	shift8(0xa1);
	ic_sda->np_piodirection=0;
	for (i = 1; i <= 8; i++)	
	{
		delayic(1);
		ic_scl->np_piodata = 0;
		delayic(1);
		ic_scl->np_piodata = 1;
		d = d << 1;
		d |=ic_sda->np_piodata;
	}
	ic_sda->np_piodirection=1;
	ic_stop();
	return d;
}

//写入数据，a为地址，b为数据
void wr_24c01(unsigned char a,unsigned char b)
{
	ic_start();
	shift8(0xa0);
	shift8(a);
	shift8(b);
	ic_stop();
}

void initialic()
{
	ic_sda->np_piodirection=1;
}