PCF8591的AD转换程序详解.doc

#include#include#define uc unsigned char#define ui unsigned intsbit P0_7=P07;sbit sda=P31;sbit scl=P30;uc shuju4;uc sec;uc code duanma= 0x3F,/*0*/ 0x06,/*1*/ 0x5B,/*2*/ 0x4F,/*3*/ 0x66,/*4*/ 0x6D,/*5*/ 0x7D,/*6*/ 0x07,/*7*/ 0x7F,/*8*/ 0x6F,/*9*/ 0x3E,/*U*/;void delay(void) _nop_(); _nop_(); _nop_(); _nop_();void delay1(void) ui i,j; for(i=0;i120;i+) for(j=0;j1;j+);void xianshi(void) uc i,j=0xfe; shuju0=10;/显示U表示电压值V shuju1=sec%10; shuju2=(sec%100)/10; shuju3=(sec%1000)/100; for(i=0;i4;i+) P0=duanmashujui; 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); void init(void) scl=1; delay(); sda=1; delay();void start(void) scl=1; delay(); sda=1; delay(); sda=0;void ack(void) ui i; scl=1; delay(); sda=1; delay(); while(sda)&(i255)i+; scl=0; delay();void noack(void) scl=1; delay(); sda=1; delay();void stop(void) sda=0; delay(); scl=1; delay(); sda=1;void write_byte(uc date) uc i,j=0x80; for(i=0;i=1; scl=1; delay(); scl=0; delay(); sda=1; delay();uc read_byte(void) uc i,j=0x80,value=0x00; for(i=0;i=1; scl=0; delay(); scl=1; delay(); sda=1; delay(); return value;void write(uc add,uc date) start(); write_byte(add); ack(); write_byte(date); ack(); stop();uc read(uc add) uc i; start(); write_byte(add+1); ack(); i=read_byte(); noack(); stop(); return i;void main(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);/