main.c

EM4094示例Firmware

          sof = 2; 
        } else {
          if ((bit_pos == 1) && (z >= (uint8_t)(pulsesPerBit2+TOLERANCE)))
            store_bit(1, 0);
          store_bit(0, 1);
        }
      } else {
        if ((bit_pos == 1) && (z >= (uint8_t)(pulsesPerBit2+TOLERANCE)))
          store_bit(1, 0);
        store_bit(0, 1);
      }
    } else {                          //raw capture

      capt >>= 5;
      store_pulse(capt);              //x
      store_pulse(z);

    }

    old_capture = icr;
  }

  last_capture = icr;
}

// ==================================================================

void dual_subcarrier_polling(void) {

  //do not use local register variables

  uint8_t z;
  uint16_t capt;
  uint16_t icr;
  uint8_t toggle;
  uint8_t x;
  uint8_t last_x;
  uint8_t y;
  uint8_t yvld;
  uint8_t correction;

  last_z = TCNT0;
  last_x = 0;
  correction = 0;
  toggle = 9 * (pulsesPerBit >> 3);

  while ( TIMSK & (1<<TOIE2) ) {          //wait until done

    z = TCNT0 - last_z;  
    if (z >= toggle) {

      icr = ICR1;   

      capt = icr - last_capture;
      x = capt >> 3;                      //(y/8)

      if ((debug_mode & 1) == 0) {        //decode

        if (capt < 2*halfDataRate) {      //if the half bit period is not so long

          x += correction;                //apply correction
          correction = 0;

          if (bit_pos == 0) {             //resolve the bit for each captured pair

            if (pulsesPerBit == 8) {      //high data rate

              if (last_x + x > 77) {        //one more pulse is measured, save it to next bit period
                correction = 4;
                x -= correction;
              } 

//              store_pulse( last_x + x );

              y = 0;
              if ( (last_x <= 0x27) && (x <= 0x27) ) y = 1;

              yvld = 0;
              if ((last_x >= 0x28) && (last_x <= 0x2A) && (x == 0x25)) yvld = 1;

//              store_pulse(last_x);
//              store_pulse(x);

              store_bit( y, yvld );
          
            } else {                      //low data rate

              if ((uint16_t)last_x + x > 0x130) {        //one more pulse is measured, save it to next bit period
                correction = 4;
                x -= correction;
              } 

              y = 0;
              if ( (last_x <= 0xA0) && (x <= 0xA0) ) y = 1;

              yvld = 0;
              if ((last_x >= 0xA1) && (last_x <= 0x2A) && (x == 0x25)) yvld = 1;

//              store_pulse(last_x);
//              store_pulse(x);

              store_bit( y, yvld );

            }

          }
          
        } else {                          //quite good pause? => error
          store_bit(0, 1);                //
        }

      } else {                            //raw data capture

        if (capt < 2*halfDataRate) {     

          x += correction;                //apply the correction
          correction = 0;

          //raw capture
          store_pulse(z);                 //z

          if (bit_pos == 0) {             //resolve the correctuib for each captured pair
            if (pulsesPerBit == 8) {      //high data rate
              if (last_x + x > 77) {      //one more pulse is measured, save it to next bit period
                correction = 4;
                x -= correction;
              }
            } else {                      //low data rate

            }
          }

          store_pulse(x);                 //y

        } else {                          //quite good pause? => error

          store_pulse(0xFF);              //
          store_pulse(capt);
          store_pulse(capt>>8);
        }

//#ifdef DEBUG
//        PORTC = PINC ^ (1<<DBG_TRANS);
//#endif
      }

      bit_pos ^= 1;
      toggle = (bit_pos | 8) * (pulsesPerBit >> 3);
      if (correction != 0) toggle--;

      last_z += z;
      last_x = x;
      last_capture = icr;
    }
  }

  //there is no information about EOF
  //data validity check is left on CRC
  sof = 2;


#if 0
//#ifdef DEBUG
  UDR = capture_cnt;
  while (!(UCSRA & (1<<UDRE)))
    {}; 
  UDR = dbg_cnt;
  while (!(UCSRA & (1<<UDRE)))
    {}; 
  UDR = x;
  while (!(UCSRA & (1<<UDRE)))
    {}; 
  UDR = TCNT0;
  while (!(UCSRA & (1<<UDRE)))
    {}; 
  UDR = last_z;
  while (!(UCSRA & (1<<UDRE)))
    {}; 
#endif
}


// ==================================================================
// Down Link setup function
// Requires: maxCaptureTimeLow and maxCaptureTimeHi
//   (located here instead of level2 because of register variables)

void Capture(uint8_t style) {

  uint8_t last_cnt;

  TCCR0 = 0;                                //disable Counter0
  TCCR1B = 0;                               //disable Counter1

  pulsesPerBit2 = 2 * pulsesPerBit;
  pulsesPerBit3 = 3 * pulsesPerBit;

  if (!bufferClean) ClearCaptureBuffers();
  bufferClean = 0;

  previous_delay = 0;
  captured_bit_count = 0;                   //reset some values
  capture_cnt = 0;
  bit_pos = 1;
  sof = 0;
  last_valid = 0;
  last_capture = TCNT1;                     
  old_capture = TCNT1;

  currentMaxTimeHi = ~maxCaptureTimeHi;     //set hi byte of maximum capture timer2 timeout
  TCNT2 = ~maxCaptureTimeLow;               //set low byte timer2 timeout
  TCNT0 = 0;                                //clear timer0
  TIFR = TIFR | (1<<ICF1) | (1<<TOV1) | TIFR | (1<<OCF2) | (1<<TOV2);      //clear pending interrupts

  sbi( TIMSK, TOIE2);                       //enable timer2 overflow for both
  if((decode_number & 1) == 0) {
    sbi( TIMSK, TICIE1 );                   //enable timer1 capture for ASK only
  }

  enable_capture = style;                   //set capture style
  TCCR0 = 6;                                //external clock source, falling edge
  TCCR1B = counter1set;                     //run! at clk
  TCCR2 = 3;                                //run! at clk/32

#if 0
//#ifdef DEBUG
  PORTD = PIND ^ (1<<DBG_FORWARD);
#endif

  if((decode_number & 1) == 0) {
    while ( TIMSK & (1<<TOIE2) )            //wait until done for ASK
      {}
  } else {
    dual_subcarrier_polling();              //do polling until done for FSK
  }

  TCCR0 = 0;                                //stop all
  TCCR1B = 0;
  TCCR2 = 0;
  TIMSK = TIMSK & (0xFF ^ ((1<<TICIE1) | (1<<TOIE2))); //disable timer1 capture, timer2 overflow
  TIFR = TIFR | (1<<ICF1) | (1<<TOV1) | TIFR | (1<<OCF2) | (1<<TOV2);      //clear pending interrupts

//#if 0
#ifdef DEBUG
  PORTD = PIND ^ (1<<DBG_FORWARD);
#endif

  last_cnt = TCNT0;  
  if (debug_mode != 1) {

    while (captured_bit_count != 0)           //flush captured bits
      store_bit(0,1);

  } else {
    if ((decode_number & 1) == 0)             //store number of pulses of last chunk for ASK
      store_pulse(last_cnt);
    else                                      //flush captured pulses for FSK
      store_pulse((uint8_t)(last_cnt - last_z));
  }

  if((decode_number & 1) == 0) {              //ASK EOF resolution
    if ((sof == 1) && (last_cnt >= (3*pulsesPerBit-TOLERANCE)) && (last_cnt <= (3*pulsesPerBit+TOLERANCE)))   //kludge for very long delays
      sof = 2; 
  }

  enable_capture = 0;
}

// ==================================================================
// Wait

void Wait(uint16_t period) {

  period = -period;
  TCCR2 = 0;                                //disable Counter2
  TCNT2 = period;                           //set timer with initial time

  TIFR = TIFR | (1<<OCF2) | (1<<TOV2);      //clear pending interrupts
  currentMaxTimeHi = period >> 8;
  sbi(TIMSK, TOIE2);                        //enable overflow

  TCCR2 = 3;                                //run! at clk/32
  while ( TIMSK & (1<<TOIE2) )              //wait until done
    {}
  TCCR2 = 0;                                //stop

#if 0
//#ifdef DEBUG
  cbi(PORTC, DBG_TRANS); 
  sbi(PORTC, DBG_TRANS); 
  cbi(PORTC, DBG_TRANS); 
#endif
}


// ==================================================================
// ==================================================================
// INTERRUPT ROUTINES
// ==================================================================

SIGNAL (SIG_OVERFLOW2)
{
  if (currentMaxTimeHi++ == 0xFF) {                 //hi datarate
    TIMSK = 0;                                    //finished, disable all
  }
}

// ==================================================================
// ==================================================================
// ==================================================================
int main(void)
{

  SetLEDOn();   

  watchdog_reset = bit_is_set(MCUCSR, WDRF);     //capture watchdog resets

  avr_ini();			                 // initialization

  main_receiver();

  return(0);
}