mirror of
https://github.com/DarkFlippers/unleashed-firmware
synced 2024-12-21 02:03:18 +00:00
67 lines
2.4 KiB
C
67 lines
2.4 KiB
C
/* Ford tires TPMS. Usually 443.92 Mhz FSK (in Europe).
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*
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* 52 us short pules
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* Preamble: 0101010101010101010101010101
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* Sync: 0110 (that is 52 us gap + 104 us pulse + 52 us gap)
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* Data: 8 bytes Manchester encoded
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* 01 = zero
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* 10 = one
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*/
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#include "../../app.h"
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static bool decode(uint8_t *bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo *info) {
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const char *sync_pattern = "010101010101" "0110";
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uint8_t sync_len = 12+4; /* We just use 12 preamble symbols + sync. */
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if (numbits-sync_len < 8*8) return false;
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uint64_t off = bitmap_seek_bits(bits,numbytes,0,numbits,sync_pattern);
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if (off == BITMAP_SEEK_NOT_FOUND) return false;
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FURI_LOG_E(TAG, "Fort TPMS preamble+sync found");
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info->start_off = off;
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off += sync_len; /* Skip preamble and sync. */
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uint8_t raw[8];
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uint32_t decoded =
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convert_from_line_code(raw,sizeof(raw),bits,numbytes,off,
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"01","10"); /* Manchester. */
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FURI_LOG_E(TAG, "Ford TPMS decoded bits: %lu", decoded);
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if (decoded < 8*8) return false; /* Require the full 8 bytes. */
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/* CRC is just the sum of the first 7 bytes MOD 256. */
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uint8_t crc = 0;
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for (int j = 0; j < 7; j++) crc += raw[j];
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if (crc != raw[7]) return false; /* Require sane CRC. */
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info->pulses_count = (off+8*8*2) - info->start_off;
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float psi = 0.25 * (((raw[6]&0x20)<<3)|raw[4]);
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/* Temperature apperas to be valid only if the most significant
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* bit of the value is not set. Otherwise its meaning is unknown.
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* Likely useful to alternatively send temperature or other info. */
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int temp = raw[5] & 0x80 ? 0 : raw[5]-56;
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int flags = raw[5] & 0x7f;
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int car_moving = (raw[6] & 0x44) == 0x44;
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snprintf(info->name,sizeof(info->name),"%s","Ford TPMS");
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snprintf(info->raw,sizeof(info->raw),"%02X%02X%02X%02X%02X%02X%02X%02X",
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raw[0],raw[1],raw[2],raw[3],raw[4],raw[5],
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raw[6],raw[7]);
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snprintf(info->info1,sizeof(info->info1),"Tire ID %02X%02X%02X%02X",
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raw[0],raw[1],raw[2],raw[3]);
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snprintf(info->info2,sizeof(info->info2),"Pressure %.2f psi", (double)psi);
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if (temp)
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snprintf(info->info3,sizeof(info->info3),"Temperature %d C", temp);
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else
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snprintf(info->info3,sizeof(info->info3),"Flags %d", flags);
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snprintf(info->info4,sizeof(info->info4),"Moving %s", car_moving ? "yes" : "no");
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return true;
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}
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ProtoViewDecoder FordTPMSDecoder = {
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"Ford TPMS", decode
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};
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