channelmonc.nc

用于传感器网络的节点操作系统 TinyOS 结构设计非常有意思

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/*
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module ChannelMonC {
  provides interface ChannelMon;
  uses {
    interface Random;
  }
}
implementation {
  enum {
    IDLE_STATE,
    START_SYMBOL_SEARCH,
    PACKET_START,
    DISABLED_STATE
  };

  enum {
    SAMPLE_RATE = 100/2*4
  };

  unsigned short CM_search[2];
  char CM_state;
  unsigned char CM_lastBit;
  unsigned char CM_startSymBits;
  short CM_waiting;

  command result_t ChannelMon.init() {
    CM_waiting = -1;
    return call ChannelMon.startSymbolSearch();
  }

  command result_t ChannelMon.startSymbolSearch() {
    //Reset to idle state.
    CM_state = IDLE_STATE;
    //set the RFM pins.
    TOSH_SET_RFM_CTL0_PIN();
    TOSH_SET_RFM_CTL1_PIN();
    TOSH_CLR_RFM_TXD_PIN();
    cbi(TIMSK, OCIE2); //clear interrupts
    cbi(TIMSK, TOIE2);  //clear interrupts
    cbi(TIMSK, OCIE2); //clear interrupts
    outp(0x09, TCCR2); //scale the counter
    outp(SAMPLE_RATE, OCR2); // set upper byte of comp reg.
    sbi(TIMSK, OCIE2); // enable timer1 interupt
    outp(0x00, TCNT2); // clear current counter value
    sbi(DDRB, 6);
    return SUCCESS;
  }



  TOSH_SIGNAL(SIG_OUTPUT_COMPARE2) {
    uint8_t bit = TOSH_READ_RFM_RXD_PIN();
    //fire the bit arrived event and send up the value.
    if (CM_state == IDLE_STATE) {
      CM_search[0] <<= 1;
      CM_search[0] = CM_search[0] | (bit & 0x1);
      if(CM_waiting != -1){
	CM_waiting --;
	if(CM_waiting == 1){
	  if ((CM_search[0] & 0xfff) == 0) {
	    CM_waiting = -1;
	    signal ChannelMon.idleDetect();
	  }else{
	    CM_waiting = (call Random.rand() & 0x1f) + 30;
	  } 
	}
      }
      if ((CM_search[0] & 0x777) == 0x707){
	CM_state = START_SYMBOL_SEARCH;
	CM_search[0] = CM_search[1] = 0;
	CM_startSymBits = 30;
      }
    }else if(CM_state == START_SYMBOL_SEARCH){
      unsigned int current = CM_search[CM_lastBit];
      CM_startSymBits--;
      if (CM_startSymBits == 0){
	CM_state = IDLE_STATE;
	return;
      }
      current <<= 1;
      current &=  0x1ff;  // start symbol is 9 bits
      if(bit) current |=  0x1;  // start symbol is 9 bits
      if (current == 0x135) {
	cbi(TIMSK, OCIE2); 
	CM_state = IDLE_STATE;
	signal ChannelMon.startSymDetect();
	return;
      }
      CM_search[CM_lastBit] = current;
      CM_lastBit ^= 1;
    }
    return;
  }

  command result_t ChannelMon.stopMonitorChannel() {
    //disable timer
    cbi(TIMSK, OCIE2); 
    CM_state = DISABLED_STATE;
    return SUCCESS;
  }

  command result_t ChannelMon.macDelay() {
    CM_search[0] = 0xff;
    if(CM_waiting == -1) {
      CM_waiting = (call Random.rand() & 0x2f) + 80;
    }
    return SUCCESS;
  }
}