//#######################################################################################################
//##                    This Plugin is only for use with the RFLink software package                   ##
//##                                        Plugin-40 Mebus                                            ##
//#######################################################################################################
/*********************************************************************************************\
 * This plugin takes care of decoding Mebus weatherstation outdoor sensors
 * It concerns Mebus sensors that are not following the Cresta (Hideki) protocol
 * Also sold as Stacja Pogody WS-9941-M
 * 
 * Author             : StuntTeam
 * Support            : http://sourceforge.net/projects/rflink/
 * License            : This code is free for use in any open source project when this header is included.
 *                      Usage of any parts of this code in a commercial application is prohibited!
 *********************************************************************************************
 * Changelog: v1.0 initial release
 *********************************************************************************************
 * Technical information:
 * Decodes signals from a Mebus Weatherstation outdoor unit, (58 pulses, 28 bits, 433 MHz).
 * Mebus Message Format: 
 * AAAA BBBB BBBB CCCC CCCC CCCC DDEF
 *
 * A = Checksum value    AAAA=((BBBB+BBBB+CCCC+CCCC+DDEF)-1)&0x0f
 * B = Changes after each reset, no change during normal operation. (Device 'Session' ID)
 * C = Temperature (21.5 degrees is shown as decimal value 215, minus values have the high bit set and need to be subtracted from a base value of 4096)
 * D = Channel number 1/2/3
 * E = Always 1
 * F = 0 when "normal" data transmit, 1 when "requested" data transmit (TX button press)
 *
 * 20;DE;DEBUG;Pulses=58;Pulses(uSec)=525,1800,350,1800,350,4275,350,1800,350,4275,350,4275,350,4275,350,1800,350,4250,350,4275,350,1800,350,4250,350,1800,350,1800,350,1800,350,1800,350,4275,350,4275,350,4250,350,1800,350,1800,350,1800,350,4275,350,4250,350,1800,350,4275,350,4275,350,4250,350;
 * 20;80;DEBUG;Pulses=58;Pulses(uSec)=450,4450,375,4450,375,4450,375,4450,375,1875,375,4450,375,4450,375,1875,375,1875,375,4425,375,4425,375,4425,375,1875,375,1875,375,1875,375,4425,375,1875,375,1875,375,1875,375,1875,375,4450,375,4450,375,1875,375,1875,375,1875,375,4450,375,4425,375,1875,375;
 * 20;81;Mebus;ID=6701;TEMP=010c;
 \*********************************************************************************************/
   // ==================================================================================
   // MEBUS bit packets 
   // 0000 1101 1001 0000 1100 1000 0111 
   // 0100 1101 1001 0000 1101 1100 0110 
   // 0100 1101 1001 0000 1100 1101 0110 
   // 1001 1101 1001 0000 1101 1100 1011 
   // 1011 1101 1001 0001 0000 1111 0110    27.1
   // 0010 0110 1110 0000 0000 1001 0110    0.9
   // 0011 0110 1110 1111 1000 0011 0110    -12.5 (1111 1000 0011=3971, 4096-3971=125
   //                  |----------|----------> temperature 0 - 51.1  
   //                |-|---------------------> set when minus temperatures -51.2 - 0
   // ==================================================================================
#define MEBUS_PULSECOUNT 58

#ifdef PLUGIN_040
boolean Plugin_040(byte function, char *string) {
      if (RawSignal.Number != MEBUS_PULSECOUNT) return false;
      unsigned long bitstream=0L;
      unsigned int temperature=0;
      byte rc=0;
      byte checksum=0;
      byte data[7];
      byte channel=0;
      //==================================================================================
      // get all 28 bits
      for(byte x=2;x <=MEBUS_PULSECOUNT-2;x+=2) {
         if (RawSignal.Pulses[x+1]*RawSignal.Multiply > 550) return false; // make sure inbetween pulses are not too long
         if (RawSignal.Pulses[x]*RawSignal.Multiply > 3400) {
            bitstream = (bitstream << 1) | 0x1; 
         } else {
            if (RawSignal.Pulses[x]*RawSignal.Multiply > 2000) return false; // invalid pulse length
            if (RawSignal.Pulses[x]*RawSignal.Multiply < 1500) return false; // invalid pulse length
            bitstream = (bitstream << 1);
         }
      }
      //==================================================================================
      // Prevent repeating signals from showing up
      //==================================================================================
      if( (SignalHash!=SignalHashPrevious) || (RepeatingTimer+1000<millis() && SignalCRC != bitstream) || (SignalCRC != bitstream) ) { 
         SignalCRC=bitstream;                       // not seen the RF packet recently
         if (bitstream == 0) return false;          // Perform a sanity check
      } else {
         return true;                               // already seen the RF packet recently
      }
      //==================================================================================
      data[0] = (bitstream >> 24) & 0x0f;           // prepare nibbles from bit stream
      data[1] = (bitstream >> 20) & 0x0f;
      data[2] = (bitstream >> 16) & 0x0f;
      data[3] = (bitstream >> 12) & 0x0f;
      data[4] = (bitstream >>  8) & 0x0f;
      data[5] = (bitstream >>  4) & 0x0f;
      data[6] = (bitstream >>  0) & 0x0f;
      //==================================================================================
      // first perform a checksum check to make sure the packet is a valid mebus packet
      checksum=data[1]+data[2]+data[3]+data[4]+data[5]+data[6];
      checksum=(checksum-1)&0xf;
      if (checksum != data[0]) return false;
      //==================================================================================
      rc=(data[1]<<4) + data[2];
      channel=(data[6])>>2;
      temperature=(data[3]<<8)+(data[4]<<4)+data[5];
      if (temperature > 3000) {
         temperature=4096-temperature;              // fix for minus temperatures
         if (temperature > 0x258) return false;     // temperature out of range ( > -60.0 degrees) 
         temperature=temperature | 0x8000;          // turn highest bit on for minus values
      } else {
         if (temperature > 0x258) return false;     // temperature out of range ( > 60.0 degrees) 
      }
      //==================================================================================
      // Output
      // ----------------------------------
      sprintf(pbuffer, "20;%02X;", PKSequenceNumber++); // Node and packet number 
      Serial.print( pbuffer );
      Serial.print(F("Mebus;"));                    // Label
      sprintf(pbuffer, "ID=%02x%02x;", rc, channel);// ID    
      Serial.print( pbuffer );
      sprintf(pbuffer, "TEMP=%04x;", temperature);     
      Serial.print( pbuffer );
      Serial.println();
      //==================================================================================
      RawSignal.Repeats=true;                       // suppress repeats of the same RF packet
      RawSignal.Number=0;
      return true;
}
#endif // PLUGIN_040