iic.c

本人开发的测量水的浊度的仪器

#define IIC_C
#include "common.h"
#include "iic.h"
#include "intrins.h"
#include "stdio.h"

#define AT24CXXPAGELEN 8

#define nops(); _nop_(); _nop_(); _nop_(); _nop_();

void start()
{
	EA = 0;
	IIC_SDA = 1;
	IIC_SCL = 1;
	nops();
	IIC_SDA = 0;
	nops();
	IIC_SCL = 0;
	EA = 1;
}

void stop()
{
	EA = 0;
	IIC_SCL = 0;
	IIC_SDA = 0;
	IIC_SCL = 1;
	nops();
	IIC_SDA = 1;
	nops();
	IIC_SCL = 0;
	EA = 1;
}
/*
void ack()
{
	IIC_SCL = 0;
	IIC_SDA = 0;
	nops();
	IIC_SCL = 1;
	nops();
	IIC_SCL = 0;
	nops();
}
*/
void noack()
{
	EA = 0;
	IIC_SDA = 1;
	nops();
	IIC_SCL = 0;
	nops();
	IIC_SCL = 1;
	nops();
	IIC_SCL = 0;
	nops();
	EA = 1;
}

uchar waitack()
{
	uchar i=255;

	EA = 0;
	IIC_SDA = 1;

	while(i--)
	{
		nops();
		if(IIC_SDA == 0)
		{
			IIC_SCL = 0;
			nops();
			IIC_SCL = 1;
			nops();
			IIC_SCL = 0;
			nops();
			return 1;
		}
	}
	
	stop();
	EA = 1;

	return 0;
}

void clockout(uchar dat)
{
	uchar i;

	EA = 0;
	
	for(i=0;i<8;i++)
	{
		IIC_SCL = 0;
		nops();

		if(dat &0x80)
			IIC_SDA = 1;
	    	else
			IIC_SDA = 0;
		dat <<= 1;

		IIC_SCL = 1;
		nops();

		IIC_SCL = 0;
		nops();
	}

	EA = 1;
}

uchar clockin()
{
	uchar i;
	uchar c = 0;

	EA = 0;

	for(i=0;i<8;i++)
	{
		c <<= 1;

		IIC_SCL = 0;
		nops();

		IIC_SCL = 1;
		nops();

		IIC_SDA = 1;
		if(IIC_SDA == 1)
			c |= 0x01;

		IIC_SCL = 0;
		nops();
	}

	EA = 1;

	return c;
}

uchar readiic(uchar addr,uchar *pdat)
{
	uchar c;

	EA = 0;

	start();

	//device address
	c = 0xa0;
	clockout(c);
	if(!waitack()) return 0;

	//memory address
	c = addr;
	clockout(c);
	if(!waitack()) return 0;

	start();

	//device address
	c = 0xa1;
	clockout(c);
	if(!waitack()) return 0;

	//read data
	*pdat = clockin();

	noack();

	stop();

	EA = 1;

	return 1;
}
/*
uchar readiiccur(uchar *pdat)
{
	uchar c;

	start();

	//device address
	c = 0xa1;
	clockout(c);
	if(!waitack()) return 0;

	//read data
	*pdat = clockin();

	noack();

	stop();

	return 1;
}
*/
/*
uchar readiicpage(uchar *pdat,uchar len)
{
	uchar c,i;

	if(len > AT24CXXPAGELEN)
		return 0;

	start();

	//device address
	c = 0xa1;
	clockout(c);
	if(!waitack()) return 0;

	//read data
	for(i=0; i<len; i++)
	{
		pdat[i] = clockin();
		if(i != len-1)
			ack();
	}

	noack();

	stop();

	return 1;
}
*/
uchar writeiic(uchar addr,uchar dat)
{
	uchar c;

	EA = 0;

	start();

//device address
	c = 0xa0;
	clockout(c);
	if(!waitack()) return 0;

//memory address
	c = addr;
	clockout(c);
	if(!waitack()) return 0;

//write data
	clockout(dat);
	if(!waitack()) return 0;

	stop();

	EA = 1;

	return 1;
}
/*
uchar writeiicpage(uchar addr,uchar *pdat,uchar len)
{
	uchar i,c;

	if(len > AT24CXXPAGELEN)
		return 0;

	start();

//device address
	c = 0xa0;
	clockout(c);
	if(!waitack()) return 0;

//memory address
	c = addr;
	clockout(c);
	if(!waitack()) return 0;

//write data
	for(i=0; i<len; i++)
	{
		clockout(pdat[i]);
		if(!waitack()) return 0;
	}

	stop();

	return 1;
}
*/