unleashed-firmware/applications/plugins/protoview/protocols/tpms/ford.c
2023-01-18 22:25:39 +03:00

79 lines
2.6 KiB
C

/* Ford tires TPMS. Usually 443.92 Mhz FSK (in Europe).
*
* 52 us short pules
* Preamble: 0101010101010101010101010101
* Sync: 0110 (that is 52 us gap + 104 us pulse + 52 us gap)
* Data: 8 bytes Manchester encoded
* 01 = zero
* 10 = one
*/
#include "../../app.h"
static bool decode(uint8_t* bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo* info) {
const char* sync_pattern = "010101010101"
"0110";
uint8_t sync_len = 12 + 4; /* We just use 12 preamble symbols + sync. */
if(numbits - sync_len < 8 * 8) return false;
uint64_t off = bitmap_seek_bits(bits, numbytes, 0, numbits, sync_pattern);
if(off == BITMAP_SEEK_NOT_FOUND) return false;
FURI_LOG_E(TAG, "Fort TPMS preamble+sync found");
info->start_off = off;
off += sync_len; /* Skip preamble and sync. */
uint8_t raw[8];
uint32_t decoded = convert_from_line_code(
raw, sizeof(raw), bits, numbytes, off, "01", "10"); /* Manchester. */
FURI_LOG_E(TAG, "Ford TPMS decoded bits: %lu", decoded);
if(decoded < 8 * 8) return false; /* Require the full 8 bytes. */
/* CRC is just the sum of the first 7 bytes MOD 256. */
uint8_t crc = 0;
for(int j = 0; j < 7; j++) crc += raw[j];
if(crc != raw[7]) return false; /* Require sane CRC. */
info->pulses_count = (off + 8 * 8 * 2) - info->start_off;
float psi = 0.25 * (((raw[6] & 0x20) << 3) | raw[4]);
/* Temperature apperas to be valid only if the most significant
* bit of the value is not set. Otherwise its meaning is unknown.
* Likely useful to alternatively send temperature or other info. */
int temp = raw[5] & 0x80 ? 0 : raw[5] - 56;
int flags = raw[5] & 0x7f;
int car_moving = (raw[6] & 0x44) == 0x44;
snprintf(info->name, sizeof(info->name), "%s", "Ford TPMS");
snprintf(
info->raw,
sizeof(info->raw),
"%02X%02X%02X%02X%02X%02X%02X%02X",
raw[0],
raw[1],
raw[2],
raw[3],
raw[4],
raw[5],
raw[6],
raw[7]);
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)psi);
if(temp)
snprintf(info->info3, sizeof(info->info3), "Temperature %d C", temp);
else
snprintf(info->info3, sizeof(info->info3), "Flags %d", flags);
snprintf(info->info4, sizeof(info->info4), "Moving %s", car_moving ? "yes" : "no");
return true;
}
ProtoViewDecoder FordTPMSDecoder = {"Ford TPMS", decode};