以下代码在串口调试助手上显示：                                                       ······（省略）                                                   11-12-17 00:35:57
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                                                  11-12-17 00:35:58                                                      ······（省略）                                                 以上是正确的读出数据 但是，假如下面那行红 {MOD}的代码去掉，就会变成：                                                       ······（省略）                                                   11-12-?? 00:??:02
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                                                  11-12-17 ??:00:03
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                                                  11-12-17 ??:00:03                                                     ······（省略）                                             该显示部分居然出现问号 请大神帮帮忙解决下，就一句代码不理解，3Q，代码如下： # include <reg52.h> # define WRITE_ADDRESS 0x80
# define READ_ADDRESS  0x81 typedef unsigned char uint8;
typedef unsigned int uint16; sbit SDA = P3^4;
sbit SCK = P3^5;
sbit RST = P1^7;   uint8 Time[] = {0,0,0,17,12,7,11};        //设置DS1302的初始值，分别为：秒，分，时，日，月，周，年 void delay(uint16 counter)
{
     while(--counter);
} void DS1302_Initial()
{
     RST = 0;
     SCK = 0;
     RST = 1; 
} void DS1302_InputByte(uint8 BYTE)                          //写一个字节
{
     uint8 i;      for(i = 0;i < 8;i++)
     {
          BYTE >>= 1;
          SDA = CY;
          SCK = 1;
          SCK = 0;       } } void Write_DS1302(uint8 ADDRESS,uint8 BYTE)
{
     DS1302_Initial();
     DS1302_InputByte(ADDRESS);
     DS1302_InputByte(BYTE);
     RST = 0;                                                           //该句前面不用对SDA进行处理，不懂！！
} uint8 DS1302_OutputByte()                                     //读一个字节
{
     uint8 i;
 
     for(i = 0;i < 8;i++)
     {
          ACC >>= 1;
          if(SDA)
              ACC |= 0x80;
          SCK = 1;
          SCK = 0;
     }      return ACC;
} uint8 Read_DS1302(ADDRESS)                  //读时间子函数
{
     DS1302_Initial();
     DS1302_InputByte(ADDRESS);
     ACC = DS1302_OutputByte();
     SDA = 0;                                               //罪魁祸首，就这句如果删了就出现错误了，大大们看看为什么？
     RST = 0;
     return ACC;
} void Read_Time()                                        //读时间
{
     uint8 i,addr;
     addr = READ_ADDRESS;
     for(i = 0;i < 7;i++)                                  //读7次，存入Time数组
     {
          Time = Read_DS1302(addr);
          addr += 2;
     }
} void DS1302_If_Protece(bit Flag)                  //设置写保护或者清写保护
{
     if(Flag)
     {
          Write_DS1302(0x8e,0x80);
     }
     else
     {
          Write_DS1302(0x8e,0); 
     }
} void DS1302_SetTime()                                     //设置初始时间
{
     uint8 i,temp;      for(i = 0;i < 7;i++)                                        //转换成BCD码
     {
          temp = Time/10;
          Time = Time%10;
          Time = Time + temp * 16;
     }      temp = WRITE_ADDRESS;
     DS1302_If_Protece(0);      for(i = 0;i < 7;i++)                                         //写入DS1302
     {
          Write_DS1302(temp,Time);
          temp += 2;
     }      DS1302_If_Protece(1);
} void Serial_Initial()                                          //串口初始化
{
     TMOD = 0x20;
     SCON = 0x40;
     TH1  = 0xfd;
     TL1  = TH1;
     TR1  = 1;
} void Serial_OutputByte(uint8 Byte)
{
     SBUF = Byte;
     while(!TI);
     TI = 0;
} void Serial_OutputTime(uint8 Data)
{
     Serial_OutputByte(Data/16+'0');              //读回来的数据转换成字符送调试助手显示
     Serial_OutputByte(Data%16+'0');
} void main()
{
     Serial_Initial();
     DS1302_SetTime();
 
     while(1)
     {
          Read_Time();
          Serial_OutputTime(Time[6]);
          Serial_OutputByte('-');
          Serial_OutputTime(Time[4]);
          Serial_OutputByte('-');
          Serial_OutputTime(Time[3]);
          Serial_OutputByte(' ');
          Serial_OutputTime(Time[2]);
          Serial_OutputByte(':');
          Serial_OutputTime(Time[1]);
          Serial_OutputByte(':');
          Serial_OutputTime(Time[0]);
          Serial_OutputByte(' ');
          Serial_OutputByte(' ');
          delay(10000);
         }
}   [ 本帖最后由 lhlonng 于 2011-12-19 10:45 编辑 ] 此帖出自小平头技术问答