nRF401無線收發串口中斷服務程序

   HotPower@126.com  2004.7.18
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void sioproc() interrupt SIO_VECTOR// using 1
{
unsigned char i;
unsigned int crc;
  if (RI) {//接收中斷
    RI = 0;
    if (!nRFTXEN && SioBuffers.RXCount) {//每次接收20個數據
      i = SBUF;
      SioBuffers.RXCount --;
      SioBuffers.RXBuffers[19 - SioBuffers.RXCount] = i;
      switch(SioBuffers.RXCount) {
        case 19:
               if (i != 0x55) SioBuffers.RXCount = 20;
                 break;
        case 18:
               if (i != 0xaa) SioBuffers.RXCount = 20;
                 break;
        case 0:
               crc = 0;
               for (i = 1; i <= 8; i ++) {
                 crc = crc16r(GetRXBuffWord(i + i), crc);
               }
               if (crc != GetRXBuffWord(18))
                 SioBuffers.RXCount = 20;
                else {
                 nRFTXEN = 1;//發送
                 for (i = 0; i < 20; i ++) {
                   SioBuffers.TXBuffers[i] = SioBuffers.RXBuffers[i];
                 }
                 SioBuffers.TXMAXCount = TX_MAXCount;
                 SioBuffers.TXCount = TX_Count + 32;
                 TI = 1;//接收結束立即轉為發送
               }
               break;
      }
    } 
  }
  if (TI) {//發送中斷
    TI = 0;
    if (nRFTXEN && SioBuffers.TXCount) {
      SioBuffers.TXCount --;
      if (SioBuffers.TXCount > 19) {
        SBUF = 0x00;
      }
      else {
        SBUF = SioBuffers.TXBuffers[19 - SioBuffers.TXCount];
      }
        if (SioBuffers.TXCount == 0) {
        if (SioBuffers.TXMAXCount) {
          SioBuffers.TXMAXCount --;
          SioBuffers.TXCount = TX_Count;
        }
        else {
          nRFTXEN = 0;//發送結束立即轉為接收
          SioBuffers.RXCount = 20;
        }
      }
    }
  }
}