/* 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 bit 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) { 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[8]; 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 < 64) return false; /* Require the full 8 bytes. */ 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->info1,sizeof(info->info1),"Pressure %.2f psi", (double)kpa); snprintf(info->info2,sizeof(info->info2),"Temperature %d C", temp); return true; } ProtoViewDecoder ToyotaTPMSDecoder = { "Toyota TPMS", decode };