Method decodeLegoPowerFunctions

src/ir_Lego.hpp:144–214

* Mode is stored in the upper nibble of command */

 * Mode is stored in the upper nibble of command
 */
bool IRrecv::decodeLegoPowerFunctions() {

    /*
     * Check header timings
     * Since LEGO_HEADER_MARK is just 158 us use a relaxed threshold compare (237) for it instead of matchMark()
     */
    if (!(matchMarkWithGreaterRange(irparams.rawbuf[1], LEGO_HEADER_MARK) && (matchSpace(irparams.rawbuf[2], LEGO_HEADER_SPACE)))) {
        DEBUG_PRINTLN(F("LEGO: No header mark and space"));
        return false;
    }

    // Check we have enough data - +4 for initial gap, start bit mark and space + stop bit mark
    if (decodedIRData.rawlen != (2 * LEGO_BITS) + 4) {
        DEBUG_PRINT(F("LEGO: Data length="));
        DEBUG_PRINT(irparams.rawlen);
        DEBUG_PRINTLN(F(" is not 36"));
        return false;
    }

    decodePulseDistanceWidthData(&LegoProtocolConstants, LEGO_BITS);

    // Stop bit, use threshold decoding - not required :-)
//    if (irparams.rawbuf[3 + (2 * LEGO_BITS)] > (2 * LEGO_BIT_MARK)) {
//        DEBUG_PRINT(F("LEGO: "));
//        DEBUG_PRINTLN(F("Stop bit mark length is wrong"));
//        return false;
//    }

    // Success
    decodedIRData.flags = IRDATA_FLAGS_IS_MSB_FIRST;
    uint16_t tDecodedValue = decodedIRData.decodedRawData;
    uint8_t tToggleEscapeChannel = tDecodedValue >> (LEGO_MODE_BITS + LEGO_COMMAND_BITS + LEGO_PARITY_BITS);
    uint8_t tMode = (tDecodedValue >> (LEGO_COMMAND_BITS + LEGO_PARITY_BITS)) & 0xF;
    uint8_t tData = (tDecodedValue >> LEGO_PARITY_BITS) & 0xF; // lego calls this field "data"
    uint8_t tParityReceived = tDecodedValue & 0xF;

    // This is parity as defined in the specifications
    // But in some scans I saw 0x9 ^ .. as parity formula
    uint8_t tParityComputed = 0xF ^ tToggleEscapeChannel ^ tMode ^ tData;

    // parity check
    if (tParityReceived != tParityComputed) {
        DEBUG_PRINT(F("LEGO: Parity is not correct. expected=0x"));
        DEBUG_PRINT(tParityComputed, HEX);
        DEBUG_PRINT(F(" received=0x"));
        DEBUG_PRINT(tParityReceived, HEX);
        DEBUG_PRINT(F(", raw=0x"));
        DEBUG_PRINT(tDecodedValue, HEX);
        DEBUG_PRINT(F(", 3 nibbles are 0x"));
        DEBUG_PRINT(tToggleEscapeChannel, HEX);
        DEBUG_PRINT(F(", 0x"));
        DEBUG_PRINT(tMode, HEX);
        DEBUG_PRINT(F(", 0x"));
        DEBUG_PRINTLN(tData, HEX);
        // might not be an error, so just continue
        decodedIRData.flags = IRDATA_FLAGS_PARITY_FAILED | IRDATA_FLAGS_IS_MSB_FIRST;
    }