PCF8591的AD转换程序详解

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1、#include#include#defineucunsignedchar#defineuiunsignedintsbitP0_7=P0^7;sbitsda=P3^1;sbitscl=P3^0;ucshuju[4];ucsec;uccodeduanma[]={0x3F,/*0*/0x06,/*1*/0x5B,/*2*/0x4F,/*3*/0x66,/*4*/0x6D,/*5*/0x7D,/*6*/0x07,/*7*/0x7F,/*8*/0x6F,/*9*/0x3E,/*U*/};voiddelay(void){_nop_();_nop_();_n

2、op_();_nop_();}voiddelay1(void){uii,j;for(i=0;i<120;i++)for(j=0;j<1;j++);}voidxianshi(void){uci,j=0xfe;shuju[0]=10;//显示‘U’表示电压值‘V’shuju[1]=sec%10;shuju[2]=(sec%100)/10;shuju[3]=(sec%1000)/100;for(i=0;i<4;i++){P0=duanma[shuju[i]];if(i==3)P0_7=1;//在百位后加小数点P2=j;delay1();P0=0x00;P2=0xff;j=_crol_(j,1

3、);}}voidinit(void){scl=1;delay();sda=1;delay();}voidstart(void){scl=1;delay();sda=1;delay();sda=0;}voidack(void){uii;scl=1;delay();sda=1;delay();while((sda)&&(i<255))i++;scl=0;delay();}voidnoack(void){scl=1;delay();sda=1;delay();}voidstop(void){sda=0;delay();scl=1;delay();sda=1;}voidwrite_byte(u

4、cdate){uci,j=0x80;for(i=0;i<8;i++){scl=0;delay();sda=date&j;j>>=1;scl=1;delay();}scl=0;delay();sda=1;delay();}ucread_byte(void){uci,j=0x80,value=0x00;for(i=0;i<8;i++){scl=1;delay();if(sda)value

5、=j;j>>=1;scl=0;delay();}scl=1;delay();sda=1;delay();returnvalue;}voidwrite(ucadd,ucdate){start();write

6、_byte(add);ack();write_byte(date);ack();stop();}ucread(ucadd){uci;start();write_byte(add+1);ack();i=read_byte();noack();stop();returni;}voidmain(void){init();//I2C总线初始化write(0x90,0x40);//0x90表示器件地址为000的写操作0x40表示四路单数入00通道无增益的器件控制指令while(1){sec=2*read(0x90);//5/256约等于0.02所以0.02*100=2扩大100倍在显示的时候在百

7、位后加小数点xianshi();}write(0x90,0x44);}