/* Renault tires TPMS. Usually 443.92 Mhz FSK. * * Preamble + sync + Manchester bits. ~48us short pulse. * 9 Bytes in total not counting the preamble. */ #include "../../app.h" #define USE_TEST_VECTOR 0 static const char* test_vector = "...01010101010101010110" // Preamble + sync /* The following is Marshal encoded, so each two characters are * actaully one bit. 01 = 0, 10 = 1. */ "010110010110" // Flags. "10011001101010011001" // Pressure, multiply by 0.75 to obtain kpa. // 244 kpa here. "1010010110011010" // Temperature, subtract 30 to obtain celsius. 22C here. "1001010101101001" "0101100110010101" "1001010101100110" // Tire ID. 0x7AD779 here. "0101010101010101" "0101010101010101" // Two FF bytes (usually). Unknown. "0110010101010101"; // CRC8 with (poly 7, initialization 0). static bool decode(uint8_t* bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo* info) { if(USE_TEST_VECTOR) { /* Test vector to check that decoding works. */ bitmap_set_pattern(bits, numbytes, 0, test_vector); numbits = strlen(test_vector); } if(numbits - 12 < 9 * 8) return false; const char* sync_pattern = "01010101010101010110"; uint64_t off = bitmap_seek_bits(bits, numbytes, 0, numbits, sync_pattern); if(off == BITMAP_SEEK_NOT_FOUND) return false; FURI_LOG_E(TAG, "Renault TPMS preamble+sync found"); info->start_off = off; off += 20; /* Skip preamble. */ uint8_t raw[9]; uint32_t decoded = convert_from_line_code( raw, sizeof(raw), bits, numbytes, off, "01", "10"); /* Manchester. */ FURI_LOG_E(TAG, "Renault TPMS decoded bits: %lu", decoded); if(decoded < 8 * 9) return false; /* Require the full 9 bytes. */ if(crc8(raw, 8, 0, 7) != raw[8]) return false; /* Require sane CRC. */ info->pulses_count = (off + 8 * 9 * 2) - info->start_off; float kpa = 0.75 * ((uint32_t)((raw[0] & 3) << 8) | raw[1]); int temp = raw[2] - 30; snprintf(info->name, sizeof(info->name), "%s", "Renault 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", raw[3], raw[4], raw[5]); snprintf(info->info2, sizeof(info->info2), "Pressure %.2f kpa", (double)kpa); snprintf(info->info3, sizeof(info->info3), "Temperature %d C", temp); return true; } ProtoViewDecoder RenaultTPMSDecoder = {"Renault TPMS", decode};