蓝桥杯知识汇总

1.数码管

• 段码显示

  uchar code display[] = {0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90, 0xbf, 0xff};

• 打开或关闭数码管

  P2 = (P2 & 0x1f) | 0xc0;
  P0 = order[cnt];
  P2 &= 0x1f;
  
  P2 = (P2 & 0x1f) | 0xe0;
  P0 = display[disbuf[cnt]];
  P2 &= 0x1f;

2.LED显示

P2 = (P2 & 0x1f) | 0x80;
P0 = 0xfe;
P2 &= 0x1f;

3.系统初始化

• 关闭外设

  P2 = ((P2 & 0x1f) | 0xa0);      //关闭全部外设
  P0 = 0x00;
  P2 &= 0x1f;
  
  P2 = (P2 & 0x1f) | 0xe0;        //数码管都不显示
  P0 = 0xff;
  P2 &= 0x1f;

• 定时器设置

  TMOD = 0x01;                   //计时器0，采用方式1
  TH0 = (65536 - 2000) / 256;    //定时2ms
  TL0 = (65536 - 2000) % 256;
  
  EA = 1;                        //打开总中断
  ET0 = 1;                       //定时器中断0打开
  TR0 = 1;                       //开始计数

• 串口通信设置

  SCON = 0x50;    //工作方式1
  AUXR = 0x40;
  TMOD = 0x20;
  
  TH1 = 256 - (11059200 / 2400 / 32);    //波特率为2400
  TL1 = 256 - (11059200 / 2400 / 32);
  
  EA = 1;         //打开总中断
  ES = 1;         //打开串口中断
  TR1 = 1;        //打开计时器1

4.IIC

#define SlaveAddrW 0x90
#define SlaveAddrR 0x91
#define EEPROMW    0xa0
#define EEPROMR    0xa1

5.DS1302

• 命令字

  #define AM(X)            X
  #define PM(X)           (X + 12)
  #define DS1302_SECOND    0x80
  #define DS1302_MINUTE    0x82
  #define DS1302_HOUR      0x84
  #define DS1302_DAY       0x86
  #define DS1302_MONTH     0x88
  #define DS1302_WEEK      0x8A
  #define DS1302_YEAR      0x8C
  #define DS1302_RAM(X)   (0xC0 + (X) * 2)

• 函数操作

  //是否写保护
  void DS1302_SetProtect(bit flag){
      if (flag)  
          Write_Ds1302(0x8e, 0x80);
      else       
          Write_Ds1302(0x8e, 0x00);
  } 
  
  //设置时间
  void DS1302_SetTime(unsigned char Address, unsigned char Value){
      DS1302_SetProtect(0);
      Write_Ds1302(Address, ((Value / 10) << 4) | (Value % 10));     //将十进制数转换成BCD码
  }
  
  //转化时间格式
  void DS1302_GetTime(SYSTEMTIME *Time){
      unsigned char ReadValue;
  
      /* 将BCD码转换成十进制数 */
      ReadValue = Read_Ds1302(DS1302_MINUTE | 0x01);
      Time->minute = ((ReadValue & 0x70)>>4) * 10 + (ReadValue & 0x0f);
  
      ReadValue = Read_Ds1302(DS1302_HOUR | 0x01);
      Time->hour = ((ReadValue & 0x70)>>4) * 10 + (ReadValue & 0x0f);
  }
  
  //时间初始化
  void Time_Initial(){
      unsigned char Second;
  
      DS1302_SetTime(DS1302_HOUR, 8);
      DS1302_SetTime(DS1302_MINUTE, 30);
      DS1302_SetTime(DS1302_SECOND, 0);
  
      Second = Read_Ds1302(DS1302_SECOND | 0x01);
      if (Second & 0x80){
          DS1302_SetTime(DS1302_SECOND, 0);          //启动时钟
      }
  }

6.A/D

unsigned char Rb2_Read(){
    unsigned char dat;
    
    IIC_Start();
    IIC_SendByte(0x90);   //写入地址
    IIC_WaitAck();
    
    IIC_SendByte(0x43);   //0x43是Rb2, 0x41是光敏
    IIC_WaitAck();
        
    IIC_Start();
    IIC_SendByte(0x91);   //读命令
    IIC_WaitAck();
            
    dat = IIC_RecByte();  //读取一个字节
    IIC_Ack(0);
    IIC_Stop();

    return dat;     
}

7.EEPROM（读取和写入数据都不可中断）

unsigned char Read_EEPROM(unsigned char con){
    unsigned char dat;
    
    IIC_Start();
    IIC_SendByte(0xa0);   //写入地址
    IIC_WaitAck();
    
    IIC_SendByte(con);        //从起始位置开始读取
    IIC_WaitAck();
        
    IIC_Start();
    IIC_SendByte(0xa1);   //读命令
    IIC_WaitAck();
            
    dat = IIC_RecByte();     //读取一个字节
    IIC_Ack(0);
    IIC_Stop();

    return dat;
}


void Write_EEPROM(unsigned char date, unsigned char con){
    IIC_Start();
    IIC_SendByte(0xa0);
    IIC_WaitAck();

    IIC_SendByte(con);  
    IIC_WaitAck();
    
    IIC_SendByte(date);
    IIC_WaitAck();   
      
    IIC_Stop();  
    Delay(3);                      //写入后要注意延时一段时间
}

8.DS18B20（读取温度不可中断）

• 延时函数

  //单总线延时函数
  void Delay_OneWire(uint t) 
  {
      char  z;  
      while(t--)  
          for(z = 0; z < 12; z++); 
  }

• 读取温度

  /* 读取数据不可中断，可以采用关闭终端来实现 */
  unsigned int Read_Temperature(){
      unsigned char low,high;  
      unsigned int temp;  
      float t;
  
      init_ds18b20();          //器件初始化
      Write_DS18B20(0xcc);     //跳过读序列 
      Write_DS18B20(0x44);     //启动温度转换
      Delay_OneWire(200);      //延迟一会儿
  
      init_ds18b20();  
      Write_DS18B20(0xcc);     //同上
      Write_DS18B20(0xbe);     //读取温度
  
      low = Read_DS18B20();    //读取低位
      high = Read_DS18B20();   //读取高位
  
      temp = (high << 8) | low;
      t = temp * 0.0625;  
      temp = t + 0.5; 
  
      return temp;  
  }