mirror of
https://github.com/DarkFlippers/unleashed-firmware
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74 lines
2.6 KiB
C
74 lines
2.6 KiB
C
/* Renault tires TPMS. Usually 443.92 Mhz FSK.
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*
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* Preamble + sync + Manchester bits. ~48us short pulse.
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* 9 Bytes in total not counting the preamble. */
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#include "../../app.h"
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#define USE_TEST_VECTOR 0
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static const char* test_vector =
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"...01010101010101010110" // Preamble + sync
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/* The following is Marshal encoded, so each two characters are
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* actaully one bit. 01 = 0, 10 = 1. */
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"010110010110" // Flags.
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"10011001101010011001" // Pressure, multiply by 0.75 to obtain kpa.
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// 244 kpa here.
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"1010010110011010" // Temperature, subtract 30 to obtain celsius. 22C here.
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"1001010101101001"
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"0101100110010101"
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"1001010101100110" // Tire ID. 0x7AD779 here.
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"0101010101010101"
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"0101010101010101" // Two FF bytes (usually). Unknown.
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"0110010101010101"; // CRC8 with (poly 7, initialization 0).
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static bool decode(uint8_t* bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo* info) {
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if(USE_TEST_VECTOR) { /* Test vector to check that decoding works. */
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bitmap_set_pattern(bits, numbytes, 0, test_vector);
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numbits = strlen(test_vector);
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}
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if(numbits - 12 < 9 * 8) return false;
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const char* sync_pattern = "01010101010101010110";
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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, "Renault TPMS preamble+sync found");
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info->start_off = off;
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off += 20; /* Skip preamble. */
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uint8_t raw[9];
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uint32_t decoded = convert_from_line_code(
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raw, sizeof(raw), bits, numbytes, off, "01", "10"); /* Manchester. */
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FURI_LOG_E(TAG, "Renault TPMS decoded bits: %lu", decoded);
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if(decoded < 8 * 9) return false; /* Require the full 9 bytes. */
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if(crc8(raw, 8, 0, 7) != raw[8]) return false; /* Require sane CRC. */
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info->pulses_count = (off + 8 * 9 * 2) - info->start_off;
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float kpa = 0.75 * ((uint32_t)((raw[0] & 3) << 8) | raw[1]);
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int temp = raw[2] - 30;
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snprintf(info->name, sizeof(info->name), "%s", "Renault TPMS");
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snprintf(
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info->raw,
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sizeof(info->raw),
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"%02X%02X%02X%02X%02X%02X%02X%02X%02X",
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raw[0],
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raw[1],
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raw[2],
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raw[3],
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raw[4],
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raw[5],
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raw[6],
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raw[7],
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raw[8]);
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snprintf(info->info1, sizeof(info->info1), "Tire ID %02X%02X%02X", raw[3], raw[4], raw[5]);
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snprintf(info->info2, sizeof(info->info2), "Pressure %.2f kpa", (double)kpa);
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snprintf(info->info3, sizeof(info->info3), "Temperature %d C", temp);
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return true;
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}
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ProtoViewDecoder RenaultTPMSDecoder = {"Renault TPMS", decode};
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