/* Renault tires TPMS. Usually 443.92 Mhz FSK. * * Preamble + marshal-encoded bits. 9 Bytes in total if we don't * count the preamble. */ #include "../app.h" #define USE_TEST_VECTOR 0 static const char *test_vector = "10101010" "10101010" "10101010" "10101001" // Preamble + sync. /* The following is marshal encoded, so each two characters are * actaully one bit. 01 = 1, 10 = 0. */ "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,test_vector); numbits = strlen(test_vector); } if (numbits < 13*8) return false; const char *sync_pattern = "10101010" "10101010" "10101010" "10101001"; 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"); off += 32; /* Skip preamble. */ uint8_t raw[9]; uint32_t decoded = convert_from_line_code(raw,sizeof(raw),bits,numbytes,off, "10","01"); /* Manchester. */ FURI_LOG_E(TAG, "Renault TPMS decoded bits: %lu", decoded); if (decoded < 8*9) return false; /* Require the full 9 bytes. */ 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),"Pressure %.2f kpa", (double)kpa); snprintf(info->info2,sizeof(info->info2),"Temperature %d C", temp); return true; } ProtoViewDecoder RenaultTPMSDecoder = { "Renault TPMS", decode };