LwRx.cpp

// LwRx.cpp
//
// LightwaveRF 434MHz receiver interface for Arduino
// 
// Author: Bob Tidey (robert@tideys.net)

#include "LwRx.h"


/**
  Pin change interrupt routine that identifies 1 and 0 LightwaveRF bits
  and constructs a message when a valid packet of data is received.
**/
void LwRx::rx_process_bits() { 
   byte event = digitalRead(rx_pin); // start setting event to the current value
   unsigned long curr = micros(); // the current time in microseconds

   uint16_t dur = (curr-rx_prev);	//unsigned int
   rx_prev = curr;
   //set event based on input and duration of previous pulse
   if(dur < 120) { //120 very short
   } else if(dur < 500) { // normal short pulse
      event +=2;
   } else if(dur < 2000) { // normal long pulse
      event +=4;
   } else if(dur > 5000){ // gap between messages
      event +=6;
   } else { //2000 > 5000
      event = 8; //illegal gap
   } 
   //state machine transitions 
   switch(rx_state) {
      case rx_state_idle:
         switch(event) {
           case 7: //1 after a message gap
             rx_state = rx_state_msgstartfound;
             break;
         }
         break;
      case rx_state_msgstartfound:
         switch(event) {
            case 2: //0 160->500
             //nothing to do wait for next positive edge
               break;
            case 3: //1 160->500
               rx_num_bytes = 0;
               rx_state = rx_state_bytestartfound;
               break;
            default:
               //not good start again
               rx_state = rx_state_idle;
               break;
         }
         break;
      case rx_state_bytestartfound:
         switch(event) {
            case 2: //0 160->500
               //nothing to do wait for next positive edge
               break;
            case 3: //1 160->500
               rx_state = rx_state_getbyte;
               rx_num_bits = 0;
               break;
            case 5: //0 500->1500
               rx_state = rx_state_getbyte;
               // Starts with 0 so put this into byte
               rx_num_bits = 1;
               rx_buf[rx_num_bytes] = 0;
               break;
            default: 
               //not good start again
               rx_state = rx_state_idle;
               break;
         }
         break;
      case rx_state_getbyte:
         switch(event) {
            case 2: //0 160->500
               //nothing to do wait for next positive edge but do stats
               if(lwrx_stats_enable) {
                  lwrx_stats[rx_stat_high_max] = max(lwrx_stats[rx_stat_high_max], dur);
                  lwrx_stats[rx_stat_high_min] = min(lwrx_stats[rx_stat_high_min], dur);
                  lwrx_stats[rx_stat_high_ave] = lwrx_stats[rx_stat_high_ave] - (lwrx_stats[rx_stat_high_ave] >> 4) + dur;
               }
               break;
            case 3: //1 160->500
               // a single 1
               rx_buf[rx_num_bytes] = rx_buf[rx_num_bytes] << 1 | 1;
               rx_num_bits++;
               if(lwrx_stats_enable) {
                  lwrx_stats[rx_stat_low1_max] = max(lwrx_stats[rx_stat_low1_max], dur);
                  lwrx_stats[rx_stat_low1_min] = min(lwrx_stats[rx_stat_low1_min], dur);
                  lwrx_stats[rx_stat_low1_ave] = lwrx_stats[rx_stat_low1_ave] - (lwrx_stats[rx_stat_low1_ave] >> 4) + dur;
               }
               break;
            case 5: //1 500->1500
               // a 1 followed by a 0
               rx_buf[rx_num_bytes] = rx_buf[rx_num_bytes] << 2 | 2;
               rx_num_bits++;
               rx_num_bits++;
               if(lwrx_stats_enable) {
                  lwrx_stats[rx_stat_low0_max] = max(lwrx_stats[rx_stat_low0_max], dur);
                  lwrx_stats[rx_stat_low0_min] = min(lwrx_stats[rx_stat_low0_min], dur);
                  lwrx_stats[rx_stat_low0_ave] = lwrx_stats[rx_stat_low0_ave] - (lwrx_stats[rx_stat_low0_ave] >> 4) + dur;
               }
               break;
            default:
               //not good start again
               rx_state = rx_state_idle;
               break;
         }
         if(rx_num_bits >= 8) {
            rx_num_bytes++;
            rx_num_bits = 0;
            if(rx_num_bytes >= rx_msglen) {
               unsigned long currMillis = millis();
               if(rx_repeats > 0) {
                  if((currMillis - rx_prevpkttime) / 100 > rx_timeout) { 
                     rx_repeatcount = 1;
                  } else {
                     //Test message same as last one
                     int16_t i = rx_msglen;	//int
                     do {
                        i--;
                     }
                     while((i >= 0) && (rx_msg[i] == rx_buf[i]));
                     if(i < 0) {
                        rx_repeatcount++;
                     } else {
                        rx_repeatcount = 1;
                     }
                  }
               } else {
                  rx_repeatcount = 0;
               }
               rx_prevpkttime = currMillis;
               //If last message hasn't been read it gets overwritten
               memcpy(rx_msg, rx_buf, rx_msglen); 
               if(rx_repeats == 0 || rx_repeatcount == rx_repeats) {
                  if(rx_pairtimeout != 0) {
                     if((currMillis - rx_pairstarttime) / 100 <= rx_pairtimeout) {
                        if(rx_msg[3] == rx_cmd_on) {
                           rx_addPairFromMsg();
                        } else if(rx_msg[3] == rx_cmd_off) {
                           rx_removePair(&rx_msg[2]);
                        }
                     }
                  }
                  if(rx_reportMessage()) {
                     rx_msgcomplete = true;
                  }
                  rx_pairtimeout = 0;
               }
               // And cycle round for next one
               rx_state = rx_state_idle;
            } else {
              rx_state = rx_state_bytestartfound;
            }
         }
         break;
   }
}

/**
  Test if a message has arrived
**/
boolean LwRx::message() {
   return (rx_msgcomplete);
}

/**
  Set translate mode
**/
void LwRx::setTranslate(boolean rxtranslate) {
   rx_translate = rxtranslate;
}

/**
  Transfer a message to user buffer
**/
boolean LwRx::getMessage(byte *buf, byte len) {
  if(!rx_msgcomplete || len > rx_msglen) 
    return false;

  boolean ret = true;
  int16_t j=0,k=0;

  for(byte i=0; ret && i < rx_msglen; i++) {
    
    if(rx_translate || (len != rx_msglen)) {
      j = rx_findNibble(rx_msg[i]);
      if(j<0) 
        ret = false;
    } else {
      j = rx_msg[i];
    }

    switch(len) {
      case 4:
        if(i==9) buf[2]=j;
        if(i==2) buf[3]=j;
      case 2:
        if(i==3) buf[0]=j;
        if(i==0) buf[1]=j<<4;
        if(i==1) buf[1]+=j;
        break;
      case 10:
        buf[i]=j;
        break;
    }
  }

  rx_msgcomplete= false; 
  return ret;
}

/**
  Return time in milliseconds since last packet received
**/
unsigned long LwRx::packetInterval() {
   return millis() - rx_prevpkttime;
}

/**
  Set up repeat filtering of received messages
**/
void LwRx::setFilter(byte repeats, byte timeout) {
   rx_repeats = repeats;
   rx_timeout = timeout;
}

/**
  Add a pair to filter received messages
  pairdata is device,dummy,5*addr,room
  pairdata is held in translated form to make comparisons quicker
**/
byte LwRx::addPair(byte* pairdata) {
   if(rx_paircount < rx_maxpairs) {
      for(byte i=0; i<8; i++) {
         rx_pairs[rx_paircount][i] = rx_nibble[pairdata[i]];
      }
      rx_pairCommit();
   }
   return rx_paircount;
}

/**
  Make a pair from next message successfully received
**/
extern void LwRx::makePair(byte timeout) {
   rx_pairtimeout = timeout;
   rx_pairstarttime = millis();
}

/**
  Get pair data (translated back to nibble form
**/
extern byte LwRx::getPair(byte* pairdata, byte pairnumber) {
   if(pairnumber < rx_paircount) {
      int16_t j;	//int
      for(byte i=0; i<8; i++) {
         j = rx_findNibble(rx_pairs[pairnumber][i]);
         if(j>=0) pairdata[i] = j;
      }
   }
   return rx_paircount;
}

/**
  Clear all pairing
**/
extern void LwRx::clearPairing() {
   rx_paircount = 0;
#if EEPROM_EN
   EEPROM.write(EEPROMaddr, 0);
#endif
}

/**
  Set EEPROMAddr
**/
extern void LwRx::setEEPROMaddr(int addr) {
   EEPROMaddr = addr;
}

/**
  Return stats on high and low pulses
**/
boolean LwRx::getStats(uint16_t *stats) {	//unsigned int
   if(lwrx_stats_enable) {
      memcpy(stats, lwrx_stats, 2 * rx_stat_count);
      return true;
   } else {
      return false;
   }
}

/**
  Set stats mode
**/
void LwRx::setStatsEnable(boolean rx_stats_enable) {
   lwrx_stats_enable = rx_stats_enable;
   if(!lwrx_stats_enable) {
      //clear down stats when disabling
      memcpy(lwrx_stats, lwrx_statsdflt, sizeof(lwrx_statsdflt));
   }
}
/**
  Set pairs behaviour
**/
void LwRx::setPairMode(boolean pairEnforce, boolean pairBaseOnly) {
   rx_pairEnforce = pairEnforce;
   rx_pairBaseOnly = pairBaseOnly;
}


/**
  Set things up to receive LightWaveRF 434Mhz messages
  pin must be 2 or 3 to trigger interrupts
  !!! For Spark, any pin will work
**/
void LwRx::setup(int pin) {
   restoreEEPROMPairing();
	rx_pin = pin;
   int int_no = getIntNo(rx_pin);
   pinMode(rx_pin,INPUT);
   memcpy(lwrx_stats, lwrx_statsdflt, sizeof(lwrx_statsdflt));
}

/**
  Check a message to see if it should be reported under pairing / mood / all off rules
  returns -1 if none found
**/
boolean LwRx::rx_reportMessage() {
  if(rx_pairEnforce && rx_paircount == 0)

  return false;
  boolean allDevices;
  // True if mood to device 15 or Off cmd with Allof paramater
  allDevices = ((rx_msg[3] == rx_cmd_mood && rx_msg[2] == rx_dev_15) || 
                (rx_msg[3] == rx_cmd_off && rx_msg[0] == rx_par0_alloff));
  return (rx_checkPairs(&rx_msg[2], allDevices) != -1);
}
/**
  Find nibble from byte
  returns -1 if none found
**/
int16_t LwRx::rx_findNibble(byte data) {	//int
   int16_t i = 15;	//int
   do {
      if(rx_nibble[i] == data) break;
      i--;
   } while (i >= 0);
   return i;
}

/**
  add pair from message buffer
**/
void LwRx::rx_addPairFromMsg() {
   if(rx_paircount < rx_maxpairs) {
      memcpy(rx_pairs[rx_paircount], &rx_msg[2], 8);
      rx_pairCommit();
   }
}

/**
  check and commit pair
**/
void LwRx::rx_pairCommit() {
   if(rx_paircount == 0 || rx_checkPairs(rx_pairs[rx_paircount], false) < 0) {
#if EEPROM_EN
		for(byte i=0; i<8; i++) {
			EEPROM.write(EEPROMaddr + 1 + 8 * rx_paircount + i, rx_pairs[rx_paircount][i]);
		}
      EEPROM.write(EEPROMaddr, rx_paircount+1);
#endif
      rx_paircount++;
   }
}

/**
  Check to see if message matches one of the pairs
    if mode is pairBase only then ignore device and room
    if allDevices is true then ignore the device number
  Returns matching pair number, -1 if not found, -2 if no pairs defined
**/
int16_t LwRx::rx_checkPairs(byte *buf, boolean allDevices ) {	//int
   if(rx_paircount ==0) {
      return -2;
   } else {
      int16_t pair= rx_paircount;	//int
      int16_t j = -1;	//int
      int16_t jstart,jend;	//int
      if(rx_pairBaseOnly) {
         // skip room(8) and dev/cmd (0,1)
         jstart = 7;
         jend = 2;
      } else {
         //include room in comparison
         jstart = 8;
         //skip device comparison if allDevices true
         jend = (allDevices) ? 2 : 0;
      }
      while (pair>0 && j<0) {
         pair--;
         j = jstart;
         while(j>jend){
            j--;
            if(j != 1) {
               if(rx_pairs[pair][j] != buf[j]) {
                  j = -1;
               }
            }
         }
      }
      return (j >= 0) ? pair : -1;
   }
}

/**
  Remove an existing pair matching the buffer
**/
void LwRx::rx_removePair(byte *buf) {
   int16_t pair = rx_checkPairs(buf, false);	//int
   if(pair >= 0) {
      while (pair < rx_paircount - 1) {
         for(byte j=0; j<8;j++) {
            rx_pairs[pair][j] = rx_pairs[pair+1][j];
#if EEPROM_EN
            if(EEPROMaddr >= 0) {
               EEPROM.write(EEPROMaddr + 1 + 8 * pair + j, rx_pairs[pair][j]);
            }
#endif
         }
         pair++;
      }
      rx_paircount--;
#if EEPROM_EN
      if(EEPROMaddr >= 0) {
         EEPROM.write(EEPROMaddr, rx_paircount);
      }
#endif
   }
}

/**
   Retrieve and set up pairing data from EEPROM if used
**/
void LwRx::restoreEEPROMPairing() {
#if EEPROM_EN
	rx_paircount = EEPROM.read(EEPROMaddr);
	if(rx_paircount > rx_maxpairs) {
		rx_paircount = 0;
		EEPROM.write(EEPROMaddr, 0);
	} else {
		for( byte i=0; i < rx_paircount; i++) {
			for(byte j=0; j<8; j++) {
				rx_pairs[i][j] = EEPROM.read(EEPROMaddr + 1 + 8 * i + j);
			}
		}
	}
#endif
}
/**
   Get Int Number for a Pin
**/
int LwRx::getIntNo(int pin) {
	int number = pin;
#ifdef PIN_NUMBERS
	int pins[8] = {PIN_NUMBERS};
	int i;
	for(i=7; i>0; i--) {
		if(pin==pins[i]) {
			break;
		}
	}
	number = i;
#endif
	return number;
}