PCF8591AD转换程序.doc

#include#define uint unsigned int#define uchar unsigned charuchar code table=0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x83,0xf8,0x80,0x98,0x88,0x83,0xc6,0xa1,0x86,0x8e;sbit scl=P20;sbit sda=P21;uint baiwei,gewei,shiwei;void delay_pcf8591(uchar z);void delay(uchar z);void init_pcf8591();void start_pcf8591();void stop_pcf8591();void ack_pcf8591();void write_pcf8591_byte(uchar add);uint read_pcf8591_byte();uint readpcf8951_adc();void display();/* 主函数*/void main()init_pcf8591();while(1) display();/* 初始化函数*/void init_pcf8591()sda=1;scl=1;/* 短延时函数*/void delay_pcf8591(uchar z)while(z-);/* 长延时函数*/void delay(uchar z)uchar x,y;for(x=z;x0;x-)for(y=100;y0;y-);/* 开始函数*/void start_pcf8591()sda=1;delay_pcf8591(1);scl=1;delay_pcf8591(1);sda=0;delay_pcf8591(1);/* 停止函数*/void stop_pcf8591()sda=0;delay_pcf8591(1);scl=1;delay_pcf8591(1);sda=1;delay_pcf8591(1);/* 等待应答函数*/void ack_pcf8591()uint t;scl=1;delay_pcf8591(1);while(sda=1)&t250) t+;scl=0;delay_pcf8591(1);/* 写字节函数*/void write_pcf8591_byte(uchar add)uchar i;for(i=0;i8;i+)add=1;scl=0;delay_pcf8591(1);sda=CY;scl=1;delay_pcf8591(1);scl=0;delay_pcf8591(1);sda=1;delay_pcf8591(1);/* 读字节函数*/uint read_pcf8591_byte()uchar temp,i;for(i=0;i8;i+)scl=1;delay_pcf8591(1);temp=1;temp|=sda;scl=0;delay_pcf8591(1);return temp;/* 读pcf8591数据函数*/uint readpcf8951_adc()uint dat;start_pcf8591();write_pcf8591_byte(0x90);ack_pcf8591();write_pcf8591_byte(0x41);ack_pcf8591();start_pcf8591();write_pcf8591_byte(0x91);ack_pcf8591();dat=read_pcf8591_byte();stop_pcf8591();return dat; /* display函数*/void display()uint n;/vin;n=readpcf8951_adc();/vin=(n*50)/255);baiwei=n/100;shiwei=n/10%10;gewei=n%10;P0=tableba