这是驱动程序
#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 P3=P1^0;
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);
P1=temp;
}
} |
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