/* Toyota tires TPMS. Usually 443.92 Mhz FSK (In Europe). * * Preamble + sync + 64 bits of data. ~48us short pulse length. * * The preamble + sync is something like: * * 10101010101 (preamble) + 001111[1] (sync) * * Note: the final [1] means that sometimes it is four 1s, sometimes * five, depending on the short pulse length detection and the exact * duration of the high long pulse. After the sync, a differential * Manchester encoded payload follows. However the Flipper's CC1101 * often can't decode correctly the initial alternating pattern 101010101, * so what we do is to seek just the sync, that is "001111" or "0011111", * however we now that it must be followed by one differenitally encoded * bit, so we can use also the first symbol of data to force a more robust * detection, and look for one of the following: * * [001111]00 * [0011111]00 * [001111]01 * [0011111]01 */ #include "../../app.h" static bool decode(uint8_t* bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo* info) { if(numbits - 6 < 64 * 2) return false; /* Ask for 64 bit of data (each bit is two symbols in the bitmap). */ char* sync[] = {"00111100", "001111100", "00111101", "001111101", NULL}; int j; uint32_t off = 0; for(j = 0; sync[j]; j++) { off = bitmap_seek_bits(bits, numbytes, 0, numbits, sync[j]); if(off != BITMAP_SEEK_NOT_FOUND) { info->start_off = off; off += strlen(sync[j]) - 2; break; } } if(off == BITMAP_SEEK_NOT_FOUND) return false; FURI_LOG_E(TAG, "Toyota TPMS sync[%s] found", sync[j]); uint8_t raw[9]; uint32_t decoded = convert_from_diff_manchester(raw, sizeof(raw), bits, numbytes, off, true); FURI_LOG_E(TAG, "Toyota TPMS decoded bits: %lu", decoded); if(decoded < 8 * 9) return false; /* Require the full 8 bytes. */ if(crc8(raw, 8, 0x80, 7) != raw[8]) return false; /* Require sane CRC. */ /* We detected a valid signal. However now info->start_off is actually * pointing to the sync part, not the preamble of alternating 0 and 1. * Protoview decoders get called with some space to the left, in order * for the decoder itself to fix the signal if neeeded, so that its * logical representation will be more accurate and better to save * and retransmit. */ if(info->start_off >= 12) { info->start_off -= 12; bitmap_set_pattern(bits, numbytes, info->start_off, "010101010101"); } info->pulses_count = (off + 8 * 9 * 2) - info->start_off; float kpa = (float)((raw[4] & 0x7f) << 1 | raw[5] >> 7) * 0.25 - 7; int temp = ((raw[5] & 0x7f) << 1 | raw[6] >> 7) - 40; snprintf(info->name, sizeof(info->name), "%s", "Toyota TPMS"); snprintf( info->raw, sizeof(info->raw), "%02X%02X%02X%02X%02X%02X%02X%02X%02X", raw[0], raw[1], raw[2], raw[3], raw[4], raw[5], raw[6], raw[7], raw[8]); snprintf( info->info1, sizeof(info->info1), "Tire ID %02X%02X%02X%02X", raw[0], raw[1], raw[2], raw[3]); snprintf(info->info2, sizeof(info->info2), "Pressure %.2f psi", (double)kpa); snprintf(info->info3, sizeof(info->info3), "Temperature %d C", temp); return true; } ProtoViewDecoder ToyotaTPMSDecoder = {"Toyota TPMS", decode};