pcf8591驱动程序.txt

很实用的单片机例程

/*************************************
*        华兄 大家互相学习           *
*				     *
*	 PCF8591  驱动程序           *
*		                     *
*   http://591881218.qzone.qq.com/   *
*************************************/
#include<reg51.h>
#include<intrins.h>

#define uchar unsigned char
#define uint unsigned int 
#define Write_PCF8591 0x90
#define Read_PCF8591 0x91
#define Control_Byte 0x40
#define LED P3

sbit SCL=P2^0;
sbit SDA=P2^1;

uchar num,temp;

void delayms(uint z)
{
	uint x,y;
	for(x=0;x<z;x++)
		for(y=0;y<110;y++);
}

void delay()
{
	_nop_();_nop_();
	_nop_();_nop_();
	_nop_();_nop_();
	_nop_();_nop_();
}

void init_IIC()
{
	SDA=1;
	delay();
	SCL=1;
	delay();
}

void start()
{
	SDA=1;
	delay();
	SCL=1;
	delay();
	SDA=0;
	delay();
}

void stop()
{
	SDA=0;
	delay();
	SCL=1;
	delay();
	SDA=1;
	delay();
}

void ack()
{
	uchar i=0;
	SCL=1;
	delay();
	while((SDA==1)&&(i<250)) i++;
	SCL=0;
	delay();
}

void noack()
{
	SDA=1;
	delay();
	SCL=1;
	delay();
	SCL=0;
	delay();
}

void Write_Byte(uchar dat)
{
	uchar i;
	for(i=0;i<8;i++)
	{
		SCL=0;
		delay();
		if(dat&0x80)
		{
			SDA=1;
		}
		else
		{
			SDA=0;
		}
		dat=dat<<1;
		SCL=1;
		delay();
	}
	SCL=0;
	delay();
	SDA=1;
	delay();	
}

uchar Read_Byte()
{
	uchar i,dat;
	SCL=0;
	delay();
	SDA=1;
	delay();
	for(i=0;i<8;i++)
	{
		SCL=1;
		delay();
		dat=dat<<1;
		if(SDA)
		{
			dat++;
		}
		SCL=0;
		delay();
	}
	return dat;
}

void DAC_PCF8591(uchar add,uchar dat)
{
	start();
	Write_Byte(add);
	ack();
	Write_Byte(Control_Byte);
	ack();
	Write_Byte(dat);
	ack();
	stop();
}

uchar ADC_Read(uchar add0,uchar add1,uchar chl)
{
	uchar dat;
	start();
	Write_Byte(add0);
	ack();
	Write_Byte(Control_Byte|chl);
	ack();
	start();
	Write_Byte(add1);
	ack();
	dat=Read_Byte();
	noack();
	stop();
	return dat;
}

void main()
{
	init_IIC();
	while(1)
	{
		DAC_PCF8591(Write_PCF8591,num);
		num++;
		delayms(30);
		temp=ADC_Read(Write_PCF8591,Read_PCF8591,0);
		LED=temp;
	}
}