Files
Momentum-Firmware/applications/plugins/protoview/protocols/toyota_tpms.c
2023-01-14 08:44:32 +01:00

85 lines
2.7 KiB
C

/* 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[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. */
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};