這個是一個硬件看門狗和用at24c02保存掉電數(shù)據(jù)的程序，希望對大家有所幫助已經(jīng)測試通過的.

#includereg51.h>#include "IIC.h"#define ADDR 0x20    //存儲地址sbit led1=P2^7;       //掉電現(xiàn)象sbit led2=P2^6;     //看門狗復(fù)位現(xiàn)象sbit WDI=P2^5;     //喂狗位uint watch=100;     //喂狗次數(shù)uchar wbuf,rbuf;  //寫數(shù)據(jù)讀數(shù)據(jù)變量bit  flag=0;   //掉電標志/*******外部中斷，下降沿觸發(fā)**************/void  intinit(){EA=1;EX0=1;IT0=1;}/****************掉電中斷*****************/void int0()  interrupt 0   //掉電數(shù)據(jù)保護，燈亮了表示進入中斷一次{led1=0;wbuf=0x01;    write1char(wbuf,ADDR);    //掉電標志wbuf=PSW;write1char(wbuf,ADDR+1); //數(shù)據(jù)保護wbuf=ACC;write1char(wbuf,ADDR+2);led1=1; }/*************watch dog處理******************/void  feeddog(){if(watch>0){WDI=~WDI;     //喂狗；watch--;led2=0;  //判斷是否重啟;正常喂狗后燈亮；若是超過1.6s后則復(fù)位燈滅；}elsewatch=0;}/////////////////////////////////////////main(){watch=100;led1=1;led2=1;delay(10000);/* rbuf=read1char(ADDR);  //判斷是否為掉電if(rbuf){PSW=read1char(ADDR+1);    //恢復(fù)重要數(shù)據(jù)ACC=read1char(ADDR+2);}wbuf=0;write1char(wbuf,ADDR);   //讀出數(shù)據(jù)后把該次的狀態(tài)清零；防止下次再讀；*/intinit();while(1){feeddog();}}/*******************************************IIC*************

**********************************************/#ifndef  _IIC_H#define  _IIC_H_/***************************************************/#includeintrins.h>#define uchar unsigned char#define uint unsigned int#define SLAVE 0xa0   //IIC器件地址  注意全部接地#define Rslave SLAVE+1sbit SDA=P2^0;sbit SCL=P2^1;////////////////////////////////////////////////////////void delay(uint time){for(time;time>0;time--);}///////////////////////////////////////void start_iic(){SDA=1;SCL=1;delay(10);SDA=0;delay(10);SCL=0;}void stop_iic(){SDA=0;SCL=1;delay(10);SDA=1;delay(10);SCL=0;}void ack_iic(){SDA=0;SCL=1;delay(10);SCL=0;SDA=1;}void nack_iic(){SDA=1;SCL=1;delay(10);SCL=0;SDA=0;}////////////////////////* write 1 byte   *//////////////////////void write_byte(uchar ch){uchar i;for(i=0;i8;i++){if(ch0x80)SDA=1;elseSDA=0;SCL=1;delay(10);SCL=0;ch=ch1;}SDA=1;SCL=1;delay(10);if(SDA==1)F0=0;elseF0=1;SCL=0;}///////////////////////////*  read 1 byte  *////////////////////////uchar read_byte(){uchar i;uchar r=0;SDA=1;for(i=0;i8;i++){r=r1;SCL=1;delay(10);if(SDA==1)r++;SCL=0;}return r;}/////////////////////////* write n  byte  *////////////////////////////bit write_nbyte(uchar slave,uint addr,uchar *str,uchar numb){uchar i;start_iic();write_byte(slave);  //write  iic  addrif(F0==0)return 0;write_byte(addr);  //write  data   addrif(F0==0)return 0;for(i=0;inumb;i++)    //write data{write_byte(*str);if(F0==0)return 0;str++;}stop_iic();       //stop iicreturn(1);}//////////////////*寫一個字節(jié)*//////////////////////////////bit  write1char(uchar ch,uint addr){start_iic();  //產(chǎn)生起始信號write_byte(SLAVE);   //發(fā)送從器件地址if(F0==0) return 0;   //檢查應(yīng)答位write_byte(addr);   //發(fā)送目的地址if(F0==0) return 0;write_byte(ch);   //發(fā)送8為數(shù)據(jù)if(F0==0) return 0;stop_iic();      //停止信號return 1;}////////////////////*讀一個字節(jié)*////////////////////////////////uchar read1char(uint addr){ uchar ch;       start_iic();   write_byte(SLAVE);if(F0==0)return 0;write_byte(addr);if(F0==0)return 0;start_iic();   //再次產(chǎn)生起始信號，不能少write_byte(Rslave);  //送讀控制字if(F0==0)return 0;ch=read_byte();  //讀出指定單元的內(nèi)容nack_iic();    //非應(yīng)答信號stop_iic();return (ch); }//////////////////////////////////////////////////////////////////////////////////* read   n   byte   *//////////////////////////////////bit read_nbyte(uchar slave,uint addr,uchar *str,uchar  numb){uchar i;start_iic();write_byte(slave);  //write  iic  addrif(F0==0)return 0;write_byte(addr);  //write  data   addrif(F0==0)return 0;start_iic();   //再次產(chǎn)生起始信號，不能少write_byte(Rslave);  //送讀控制字if(F0==0)return 0;for(i=0;inumb-1;i++)    //{*str=read_byte();ack_iic();str++;}*str=read_byte();nack_iic();stop_iic();return(1);}/************************************************************/#endif