原创 Zigbee RF(无线传输)模块中断程序（无线龙版）(转载）

INTERRUPT_FUNC spp_rf_IRQ(void)
{
  BYTE flen;
  BYTE enabledAndActiveInterrupt;
  BYTE *ptr, *rx_frame;
  BYTE ack_bytes[5];
  BYTE crc;
  #define  fcflsb ack_bytes[0]
  #define  fcfmsb  ack_bytes[1]
  #define  dstmode ack_bytes[2]
  #define  srcmode ack_bytes[3]

  INT_GLOBAL_ENABLE(INT_OFF); //关闭全局中断
  enabledAndActiveInterrupt = RFIF; //读取RF中断标志
  RFIF = 0x00; //清空RF中断标志
  INT_SETFLAG_RF(INT_CLR);  // Clear MCU interrupt flag
  enabledAndActiveInterrupt &= RFIM; //读取RF中断屏蔽（控制RF中断使能）
 // 处理受到的数据

  if(enabledAndActiveInterrupt & IRQ_FIFOP) //数据溢出中断
  {
    DEBUG_CHAR( DBG_ITRACE,DBG_CHAR_RXRCV );
    //if last packet has not been processed, we just
    //read it but ignore it.
    ptr = NULL; //temporary pointer
    flen = RFD & 0x7f; //读数据长度（注意帧的格式）
    if (flen == LRWPAN_ACKFRAME_LENGTH) {
     //this should be an ACK.
      //read the packet, do not allocate space for it
      DEBUG_CHAR( DBG_ITRACE,DBG_CHAR_ACKPKT );
      ack_bytes[0]= flen;
      ack_bytes[1] =  RFD; //LSB Frame Control Field
      ack_bytes[2] = RFD;  //MSB Frame Control Field
      ack_bytes[3] = RFD;  //dsn
      ack_bytes[4] = RFD;  //RSSI
      crc = RFD;
     //check CRC
      if (crc & 0x80){
       // CRC ok, perform callback if this is an ACK
        macRxCallback(ack_bytes, ack_bytes[4]);
      }

    }else {
     //not an ack packet, lets do some more early rejection
      // that the CC2430 seems to not do that we want to do.
      //read the fcflsb, fcfmsb
      fcflsb = RFD;
      fcfmsb = RFD;
      if (!local_radio_flags.bits.listen_mode) {
       //only reject if not in listen mode
        //get the src, dst addressing modes
        srcmode = LRWPAN_GET_SRC_ADDR(fcfmsb);
        dstmode = LRWPAN_GET_DST_ADDR(fcfmsb);
        if ((srcmode == LRWPAN_ADDRMODE_NOADDR) && (dstmode == LRWPAN_ADDRMODE_NOADDR)) {
         //reject this packet, no addressing info
          goto do_rxflush;
        }
      }

      if (!macRxBuffFull()) {
       //MAC TX buffer has room
        //allocate new memory space
        //read the length
        rx_frame = MemAlloc(flen+1);
        ptr = rx_frame;
      } else {
        //MAC RX buffer is full
        DEBUG_CHAR( DBG_ITRACE,DBG_CHAR_MACFULL );
      }

      // at this point, if ptr is null, then either
      // the MAC RX buffer is full or there is  no
      // free memory for the new frame, or the packet is
      // going to be rejected because of addressing info.
      // In these cases, we need to
      // throw the RX packet away
      if (ptr == NULL) {
       //just flush the bytes
        goto do_rxflush;
      }else {
       //save packet, including the length
        *ptr = flen; ptr++;
       //save the fcflsb, fcfmsb bytes
        *ptr = fcflsb; ptr++; flen--;
        *ptr = fcfmsb; ptr++; flen--;
       //get the rest of the bytes
        while (flen) { *ptr = RFD;  flen--; ptr++; }
       //do RX callback
        //check the CRC
        if (*(ptr-1) & 0x80) {
          //CRC good
          //change the RSSI byte from 2's complement to unsigned number
          *(ptr-2) = *(ptr-2) + 0x80;
          phyRxCallback();
          macRxCallback(rx_frame, *(ptr-2));
        }else {
          // CRC bad. Free the packet
          MemFree(rx_frame);
        }
      }
    }

   //flush any remaining bytes
  do_rxflush:
      ISFLUSHRX;
      ISFLUSHRX;

   //don't know why, but the RF flags have to be cleared AFTER a read is done.
    RFIF = 0x00;
    INT_SETFLAG_RF(INT_CLR);   // Clear MCU interrupt flag
    //don't know why, but the interrupt mask has to be set again here for some reason.
    //the processor receives packets, but does not generate an interrupt
    RFIM |= IRQ_FIFOP;
 } //end receive interrupt (FIFOP)

 // Transmission of a packet is finished. Enabling reception of ACK if required.
  if(enabledAndActiveInterrupt & IRQ_TXDONE)
  {
   //Finished TX, do call back
    DEBUG_CHAR( DBG_ITRACE,DBG_CHAR_TXFIN );
    phyTxEndCallBack();
    macTxCallback();
   // Clearing the tx done interrupt enable
    RFIM &= ~IRQ_TXDONE;

  }
  usrIntCallback();
  INT_GLOBAL_ENABLE(INT_ON);

#undef  fcflsb
#undef  fcfmsb
#undef  dstmode
#undef  srcmode
}

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