20鍵PS2小鍵盤中斷服務程序
 

/*------------------------------------
     PS2鍵盤外部INT1中斷服務程序

原創:           HotPower@126.com   
------------------------------------*/
void int1proc() interrupt IE1_VECTOR using 1
{
unsigned char i, key;
code unsigned char PS2TAB[] = {//20鍵PS2小鍵盤鍵碼表
  0x70,//0
  0x69,//1
  0x72,//2
  0x7a,//3
  0x6b,//4
  0x73,//5
  0x74,//6
  0x6c,//7
  0x75,//8
  0x7d,//9
  0x05,//F1
  0x06,//F2
  0x04,//F3
  0x0c,//F4
  0x03,//F5
  0x0b,//F6
  0x5a,//Enter
  0x76,//Esc
  0x66,//Bksp
  0x71//KP.
  };
  if (PS2Buffers.PS2KeyCount == 0){//PS2起始位測試
    if (!PS2CLOCK && !PS2DATA){//低電平是起始位
      if (PS2Buffers.PS2KeyExtFlage != 0xf0){
        PS2Buffers.PS2KeyTemp = 0;
        PS2Buffers.PS2KeyExtFlage = 0;
        PS2Buffers.PS2KeyPopError = 0;
      }
      PS2Buffers.PS2KeyCount ++;//脈沖計數
    }
    else PS2Buffers.PS2KeyPopError = 0xeb;//置鍵起始位錯誤號0xeb
  }
  else if (PS2Buffers.PS2KeyCount < 9){//PS2數據位
    key = PS2Buffers.PS2KeyTemp;//取鍵盤緩沖區移位數據
    key >>= 1;
    if (PS2DATA) key |= 0x80;
    PS2Buffers.PS2KeyTemp = key;
    PS2Buffers.PS2KeyCount++;//脈沖計數
  }
  else if (PS2Buffers.PS2KeyCount == 9){//PS2數據奇校驗
    ACC = PS2Buffers.PS2KeyTemp;//取鍵盤緩沖區移位數據(C51取偶校驗位)
    if (P != PS2DATA) PS2Buffers.PS2KeyCount ++;//脈沖計數
    else{
      PS2Buffers.PS2KeyPopError = 0xec;////置鍵奇校驗位錯誤號0xec
      PS2Buffers.PS2KeyCount = 0;//脈沖計數歸零
    }
  }
  else if (PS2Buffers.PS2KeyCount == 10){//停止位
    key = PS2Buffers.PS2KeyTemp;//取鍵盤緩沖區移位數據
    PS2Buffers.PS2KeyCount = 0;//脈沖計數歸零
    if (PS2DATA){//高電平是停止位
      if (key == 0xe0){//本次是擴展鍵
        PS2Buffers.PS2KeyExtFlage = 0xe0;//置擴展鍵標志(小鍵盤只有回車鍵)
      }
      else if (key == 0xf0){//本次是鍵斷碼，鍵釋放
        PS2Buffers.PS2KeyExtFlage = 0xf0;//置鍵釋放標志
      }
      else{//本次必為鍵值
        if ((key == 0xaa) || (key == 0xfa)) PS2Buffers.PS2KeyPushCount = 0;//長
壓鍵計數器清零
        else{
            PS2CLOCK = 0;//阻止PS2鍵盤立即回送數據
          PS2Buffers.PS2KeyPopError = 0xaa;//出錯碼
          for (i = 0; i < 20; i++){
            if (key == (PS2TAB[i])){//搜索
              key = i + 1;
              if (PS2Buffers.PS2KeyExtFlage == 0xf0){
                key |= 0x80;//鍵釋放
                PS2Buffers.PS2KeyPushCount = 0;//長壓鍵計數器清零
                PS2Buffers.PS2KeyMessage = key;//存入當前鍵值并執行命令
              }
              else{
                if (key != PS2Buffers.PS2KeyVal){//換了一個鍵
                  PS2Buffers.PS2KeyPushCount = 0;//長壓鍵計數器清零
                  PS2Buffers.PS2KeyMessage = key;//存入當前鍵值并執行命令
                }
                else{//未換鍵
                  PS2Buffers.PS2KeyPushCount ++;//長壓鍵計數器計數
                  if (PS2Buffers.PS2KeyPushCount > DEFPS2PUSHCOUNT){//長壓時間到
                    PS2Buffers.PS2KeyMessage = key | 0x40;//存入當前鍵值并執行命
令
                    PS2Buffers.PS2KeyPushCount = 0;//長壓鍵計數器清零
                  }
                }
              }
              PS2Buffers.PS2KeyVal = key;//存入當前鍵值值1~20或0x80+(1~20)
              PS2Buffers.PS2KeyTemp = 0;//鍵碼移位記錄器
              PS2Buffers.PS2KeyExtFlage = 0;//擴展鍵標志
              PS2Buffers.PS2KeyPopError = 0;//鍵釋放標志或出錯碼
              break;
            }
          }
          if (PS2Buffers.PS2KeyPopError) PS2Buffers.PS2KeyPushCount = 0;//長壓鍵
計數器清零
          PS2CLOCK = 1;//釋放PS2時鐘總線
        }
      }
    }
    else PS2Buffers.PS2KeyPopError = 0xed;//置停止位錯誤號0xed
  }
  else PS2Buffers.PS2KeyCount = 0;//PS2鍵盤出錯
}