irRecv.cpp

00001 #include "IRremote.h"
00002 #include "IRremoteInt.h"
00003 
00004 //+=============================================================================
00005 // Decodes the received IR message
00006 // Returns 0 if no data ready, 1 if data ready.
00007 // Results of decoding are stored in results
00008 //
00009 int  IRrecv::decode (decode_results *results)
00010 {
00011     results->rawbuf   = irparams.rawbuf;
00012     results->rawlen   = irparams.rawlen;
00013 
00014     results->overflow = irparams.overflow;
00015 
00016     if (irparams.rcvstate != STATE_STOP)  return false ;
00017 
00018 #if DECODE_NEC
00019     DBG_PRINTLN("Attempting NEC decode");
00020     if (decodeNEC(results))  return true ;
00021 #endif
00022 
00023 #if DECODE_SONY
00024     DBG_PRINTLN("Attempting Sony decode");
00025     if (decodeSony(results))  return true ;
00026 #endif
00027 
00028 #if DECODE_SANYO
00029     DBG_PRINTLN("Attempting Sanyo decode");
00030     if (decodeSanyo(results))  return true ;
00031 #endif
00032 
00033 #if DECODE_MITSUBISHI
00034     DBG_PRINTLN("Attempting Mitsubishi decode");
00035     if (decodeMitsubishi(results))  return true ;
00036 #endif
00037 
00038 #if DECODE_RC5
00039     DBG_PRINTLN("Attempting RC5 decode");
00040     if (decodeRC5(results))  return true ;
00041 #endif
00042 
00043 #if DECODE_RC6
00044     DBG_PRINTLN("Attempting RC6 decode");
00045     if (decodeRC6(results))  return true ;
00046 #endif
00047 
00048 #if DECODE_PANASONIC
00049     DBG_PRINTLN("Attempting Panasonic decode");
00050     if (decodePanasonic(results))  return true ;
00051 #endif
00052 
00053 #if DECODE_LG
00054     DBG_PRINTLN("Attempting LG decode");
00055     if (decodeLG(results))  return true ;
00056 #endif
00057 
00058 #if DECODE_JVC
00059     DBG_PRINTLN("Attempting JVC decode");
00060     if (decodeJVC(results))  return true ;
00061 #endif
00062 
00063 #if DECODE_SAMSUNG
00064     DBG_PRINTLN("Attempting SAMSUNG decode");
00065     if (decodeSAMSUNG(results))  return true ;
00066 #endif
00067 
00068 #if DECODE_WHYNTER
00069     DBG_PRINTLN("Attempting Whynter decode");
00070     if (decodeWhynter(results))  return true ;
00071 #endif
00072 
00073 #if DECODE_AIWA_RC_T501
00074     DBG_PRINTLN("Attempting Aiwa RC-T501 decode");
00075     if (decodeAiwaRCT501(results))  return true ;
00076 #endif
00077 
00078 #if DECODE_DENON
00079     DBG_PRINTLN("Attempting Denon decode");
00080     if (decodeDenon(results))  return true ;
00081 #endif
00082 
00083     // decodeHash returns a hash on any input.
00084     // Thus, it needs to be last in the list.
00085     // If you add any decodes, add them before this.
00086     if (decodeHash(results))  return true ;
00087 
00088     // Throw away and start over
00089     resume();
00090     return false;
00091 }
00092 
00093 //+=============================================================================
00094 IRrecv::IRrecv (PinName recvpin) : _recvpin(recvpin)
00095 {
00096     _recvpin.mode(PullNone);
00097 }
00098 
00099 //+=============================================================================
00100 // enable IR receive
00101 //
00102 void  IRrecv::enableIRIn ( )
00103 {
00104     _ticker.detach();
00105     _ticker.attach_us(callback(this, &IRrecv::timer_isr), USECPERTICK);
00106     _ticker.attach_us(this, &IRrecv::timer_isr, USECPERTICK);
00107 
00108     // Initialize state machine variables
00109     irparams.rcvstate = STATE_IDLE;
00110     irparams.rawlen = 0;
00111 }
00112 
00113 //+=============================================================================
00114 // disable IR receive
00115 //
00116 void  IRrecv::disableIRIn ( )
00117 {
00118     _ticker.detach();
00119 }
00120 
00121 //+=============================================================================
00122 // Return if receiving new IR signals
00123 // 
00124 bool  IRrecv::isIdle ( ) 
00125 {
00126     return irparams.rcvstate == STATE_IDLE || irparams.rcvstate == STATE_STOP;
00127 }
00128 
00129 //+=============================================================================
00130 // Restart the ISR state machine
00131 //
00132 void  IRrecv::resume ( )
00133 {
00134     irparams.rcvstate = STATE_IDLE;
00135     irparams.rawlen = 0;
00136 }
00137 
00138 //+=============================================================================
00139 // hashdecode - decode an arbitrary IR code.
00140 // Instead of decoding using a standard encoding scheme
00141 // (e.g. Sony, NEC, RC5), the code is hashed to a 32-bit value.
00142 //
00143 // The algorithm: look at the sequence of MARK signals, and see if each one
00144 // is shorter (0), the same length (1), or longer (2) than the previous.
00145 // Do the same with the SPACE signals.  Hash the resulting sequence of 0's,
00146 // 1's, and 2's to a 32-bit value.  This will give a unique value for each
00147 // different code (probably), for most code systems.
00148 //
00149 // http://arcfn.com/2010/01/using-arbitrary-remotes-with-arduino.html
00150 //
00151 // Compare two tick values, returning 0 if newval is shorter,
00152 // 1 if newval is equal, and 2 if newval is longer
00153 // Use a tolerance of 20%
00154 //
00155 int  IRrecv::compare (unsigned int oldval,  unsigned int newval)
00156 {
00157     if      (newval < oldval * .8)  return 0 ;
00158     else if (oldval < newval * .8)  return 2 ;
00159     else                            return 1 ;
00160 }
00161 
00162 //+=============================================================================
00163 // Use FNV hash algorithm: http://isthe.com/chongo/tech/comp/fnv/#FNV-param
00164 // Converts the raw code values into a 32-bit hash code.
00165 // Hopefully this code is unique for each button.
00166 // This isn't a "real" decoding, just an arbitrary value.
00167 //
00168 #define FNV_PRIME_32 16777619
00169 #define FNV_BASIS_32 2166136261
00170 
00171 long  IRrecv::decodeHash (decode_results *results)
00172 {
00173     unsigned long  hash = FNV_BASIS_32;
00174 
00175     // Require at least 6 samples to prevent triggering on noise
00176     if (results->rawlen < 6)  return false ;
00177 
00178     for (int i = 1;  (i + 2) < results->rawlen;  i++) {
00179         int value =  compare(results->rawbuf[i], results->rawbuf[i+2]);
00180         // Add value into the hash
00181         hash = (hash * FNV_PRIME_32) ^ value;
00182     }
00183 
00184     results->value       = hash;
00185     results->bits        = 32;
00186     results->decode_type = UNKNOWN;
00187 
00188     return true;
00189 }