//使用PIC16F917的片子,使用T0中断查询方式接收遥控命令
//************************************************************************************************************
#include <pic.h>;
void main(void);
void interrupt ISR(void);
void sub_cpu_ini(void);
//************************************************************************************************************
unsigned char hh_w,ll_w;           //高,低电平宽度
unsigned char ma_x;                //接收到第几位编码了
unsigned char bma1,bma2,bma3,bma4; //用于接收过程存放遥控编码
unsigned char mma1,mma2,mma3,mma4; //用于解码过程
          bit rf_ok;               //接收到一个完整的遥控命令后置1,通知解码程序可以解码了
          bit old_rc5;             //保存上一次查询到的电平状态
          bit tb_ok;               //接收到同步的马时置1
void main()
{
  sub_cpu_ini(); 
}         
//***************************************************************************************************
//----- 中断服务程序                                                                          -----//
//***************************************************************************************************
void  interrupt ISR(void)    //只启用了T0中断，所以不用判断中断源
   {  T0IF=0;                // 清除T0中断标志
      #asm
        clrwdt                //喂狗
      #endasm              
      TMR0=125;              //将T0中断时间修正为150uS
      RC3=!RC3;              //连接逻辑分析仪,查看T0中断时间间隔
          
      if (!RC5) { ll_w++;old_rc5=0; }           // 检测到低电平 低电平时间加1,记录本次电平状态
      else                                      // 检测到高电平
       { hh_w++;
         if (!old_rc5)                          // 检测到从低到高的跳变,已检测到一个完整(高-低)电平周期
          { if (((hh_w>=2)&&(hh_w<=3))&&((ll_w>=60)&&(ll_w<=80)))          //判同步码
             { ma_x=0; tb_ok=1; bma1=0; bma2=0; bma3=0; bma4=0;
             }
            else if ((tb_ok)&&((ll_w>=6)&&(ll_w<=9))) { ma_x++; }    //已经接收到同步码,判0
            else if ((tb_ok)&&((ll_w>=2)&&(ll_w<=3))) 
                  { switch (ma_x)
                     { case 0 : { bma1=bma1 | 0B10000000; break; }//遥控编码第1位
                       case 1 : { bma1=bma1 | 0B01000000; break; }
                       case 2 : { bma1=bma1 | 0B00100000; break; }
                       case 3 : { bma1=bma1 | 0B00010000; break; }
                       case 4 : { bma1=bma1 | 0B00001000; break; }
                       case 5 : { bma1=bma1 | 0B00000100; break; }
                       case 6 : { bma1=bma1 | 0B00000010; break; }
                       case 7 : { bma1=bma1 | 0B00000001; break; }
                       case 8 : { bma2=bma2 | 0B10000000; break; }
                       case 9 : { bma2=bma2 | 0B01000000; break; }
                       case 10: { bma2=bma2 | 0B00100000; break; }
                       case 11: { bma2=bma2 | 0B00010000; break; }
                       case 12: { bma2=bma2 | 0B00001000; break; }
                       case 13: { bma2=bma2 | 0B00000100; break; }
                       case 14: { bma2=bma2 | 0B00000010; break; }
                       case 15: { bma2=bma2 | 0B00000001; break; }
                       case 16: { bma3=bma3 | 0B10000000; break; }
                       case 17: { bma3=bma3 | 0B01000000; break; }
                       case 18: { bma3=bma3 | 0B00100000; break; }
                       case 19: { bma3=bma3 | 0B00010000; break; }
                       case 20: { bma4=bma4 | 0B10000000; break; }//按键状态第1位
                       case 21: { bma4=bma4 | 0B01000000; break; }
                       case 22: { bma4=bma4 | 0B00100000; break; }
                       case 23: { bma4=bma4 | 0B00010000;
                                  mma1=bma1;mma2=bma2;mma3=bma3;mma4=bma4;//将接收到的编码复制到解码寄存器中
//在下一行设一个断点，用ICD2调试                                 
                                  rf_ok=1;                                // 通知解码子程序可以解码了
                                  break;
                                }
                     }
                    ma_x++;
                  }
            else {ma_x=0; tb_ok=0; bma1=0; bma2=0; bma3=0; bma4=0;}      //接收到不符合的高-低电平序列
     ll_w=0;hh_w=1;
   }         
         old_rc5=1;      // 记录本次电平状态
       }
   }
//***************************************************************************************************
//----- 上电初始化程序                                                                        -----//
//***************************************************************************************************
void sub_cpu_ini()
  { PORTA  =0B11110000; PORTB=0B11011100; PORTC=0B00111011; PORTE=0B11111111;
    TRISA  =0B11110000; TRISB=0B11111111; TRISC=0B00110011; TRISE=0B11111111;
    WPUB   =0B11011101;
    OSCCON =0B01100111;         //使用片内振荡频率 4MHZ
    ANSEL  =0B00000000;         //模拟输入管脚配置为通用I/O口
    CMCON0 =0B00000111;         //关闭模拟比较器
    OPTION =0B00001111;         //对T0初始化,WDT预分频128
    LCDCON =0B00000011;         //VLCD引脚禁止(RC0,RC1,RC2) 
    T2CON  =0B00000011;         //设置T2为4096uS中断一次,作为一次处理循环
    TMR1ON=0;                   //关闭Timer1
    TMR2ON=0;                   //关闭Timer2
    T0IF  =0;                   //清除T0中断标志
    TMR2IF=0;                   //清除T2中断标志
    T0IE  =1;                   //允许T0中断
//    GIE   =1;                 //打开全局中断
    TMR2ON=1;                   //打开Timer2
  }