//#include <reg52.h>
//#include <stdio.h>
//下面是我正在用的没有问题。
sbit SO=P2^2;
sbit SI=P2^1;
sbit SCK=P2^0;
sbit CS=P3^6;
//25045可编程看门狗监控EEPROM指令集
#define WREN 0x06;  00000110   //设置写使能锁存器（允许写操作)
#define WRDI 0x04;  00000100   //复位写使能锁存器（禁止写操作）
#define RDSR 0x05;  00000101   //读状态寄存器
#define WRSR 0x01;  00000001   //写状态寄存器（块锁定）
#define READ 0x03;  00000011  //从开始于所选地址的存储器列阵中读出数据
#define WRTE 0x02;  00000010  //把数据写入开始于所选地址的存储器阵列中（1至4字
节）
void in_byte(unsigned char BYT);
unsigned char out_byte(void);
unsigned char rdsr_dog(void);
void wrsr_dog(unsigned char status_reg);
unsigned char  wip_poll(void);
void wrdi_dog(void);
void rest_dog(void);
unsigned char byte_read(unsigned char H,unsigned char L);
void byte_write(unsigned char H,unsigned char L,unsigned char D);
//void page_read(unsigned char H,unsigned char L,unsigned char D);
//void page_write(unsigned char H,unsigned char L,unsigned char D);
unsigned char rda[8];
unsigned char cs_rda[8];    
//看门狗写使能子程序
void wren_dog(void)
{
 //   unsigned char com;
   // com=0x06;//WREN;
    SCK=0;
    CS=0;
    in_byte(0x06);
    SCK=0;
    CS=1;
}
//看门狗写禁止子程序
void wrdi_dog(void)
{
    //unsigned char com;
    //com=0x04;//WRDI;
    SCK=0;
    CS=0;
    in_byte(0x04);
    SCK=0;
    CS=1;
}
//写状态寄存器
void wrsr_dog(unsigned char status_reg)
{
 //   unsigned char com=0x01;//WRSR;
    SCK=0;
    CS=0;
    in_byte(0x01);
    in_byte(status_reg);
    SCK=0;
    CS=1;
    wip_poll();
}
//读状态寄存器
unsigned char rdsr_dog(void)
{
  //  unsigned char com=0x05;//RDSR;
    SCK=0;
    CS=0;
    in_byte(0x05);
    return(out_byte());
    SCK=0;
    CS=1;
}
//字节读
unsigned char byte_read(unsigned char H,unsigned char L)
{
    unsigned char data_dog,add;
    SCK=0;
    CS=0;
    SO=1;
    SI=1;
    add=H<<3;
    add|=0x03;//READ;
    in_byte(add);
    add=L;
    in_byte(add);
    data_dog=out_byte();
    SCK=0;
    CS=1;
    return(data_dog);
}
//字节写
//H,地址高字节；L地址低字节；D写入的数据
void byte_write(unsigned char H,unsigned char L,unsigned char D)
{
    unsigned char data_dog,add;
    SCK=0;
    CS=0;
    SO=1;
    SI=1;
    add=H<<3;
    add|=0x02;//WRTE;
    in_byte(add);
    add=L;
    in_byte(add);
    data_dog=D;
    in_byte(data_dog);
    CS=1;
    wip_poll();
}
//复位看门狗子程序
void rest_dog(void)
{
    CS=0;
    CS=1;
}
//检验写操作是否结束。
unsigned char  wip_poll(void)
{
    unsigned char i;
    unsigned char wip;
    for(i=0xff;i>=1;i--)    
    {
        wip=rdsr_dog();
        wip&=0x01;
        if(wip==0) break;
    }
    return(wip);
}
//单字节指令或数据写入X25045
//在SI线上输入的数据在SCK的上升沿被锁存。
void in_byte(unsigned char byt)
{
    unsigned char i;
    //SCK=0;
    //CS=0;
    for(i=8;i>=1;i--)
    {
        SCK=0;        
        SI=byt&0x80;        
        SCK=1;        
    byt=byt<<1; 
   }
//    SI=0;
//    SCK=0;
   // CS=1;
}
//单字节数据从X25045读到单片机
//数据由SCK的下降沿输出到SO线上。
unsigned char out_byte(void)
{
    unsigned char i;
    unsigned char byt;
    //SO=1;
    //SCK=0;
    //CS=0;
    for(i=8;i>=1;i--)
    {
       byt=byt<<1;
       SCK=1;
       SCK=0; 
       byt|=SO;   
    }
    //SCK=0;
    //CS=1;
    return (byt);
}