mirror of
https://github.com/DarkFlippers/unleashed-firmware
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119 lines
4.6 KiB
C
119 lines
4.6 KiB
C
/* Copyright (C) 2022-2023 Salvatore Sanfilippo -- All Rights Reserved
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* See the LICENSE file for information about the license.
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*
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* 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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uint8_t flags = raw[0] >> 2;
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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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fieldset_add_bytes(info->fieldset, "Tire ID", raw + 3, 3 * 2);
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fieldset_add_float(info->fieldset, "Pressure kpa", kpa, 2);
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fieldset_add_int(info->fieldset, "Temperature C", temp, 8);
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fieldset_add_hex(info->fieldset, "Flags", flags, 6);
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fieldset_add_bytes(info->fieldset, "Unknown1", raw + 6, 2);
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fieldset_add_bytes(info->fieldset, "Unknown2", raw + 7, 2);
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return true;
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}
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/* Give fields and defaults for the signal creator. */
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static void get_fields(ProtoViewFieldSet* fieldset) {
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uint8_t default_id[3] = {0xAB, 0xCD, 0xEF};
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fieldset_add_bytes(fieldset, "Tire ID", default_id, 3 * 2);
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fieldset_add_float(fieldset, "Pressure kpa", 123, 2);
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fieldset_add_int(fieldset, "Temperature C", 20, 8);
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// We don't know what flags are, but 1B is a common value.
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fieldset_add_hex(fieldset, "Flags", 0x1b, 6);
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fieldset_add_bytes(fieldset, "Unknown1", (uint8_t*)"\xff", 2);
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fieldset_add_bytes(fieldset, "Unknown2", (uint8_t*)"\xff", 2);
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}
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/* Create a Renault TPMS signal, according to the fields provided. */
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static void build_message(RawSamplesBuffer* samples, ProtoViewFieldSet* fieldset) {
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uint32_t te = 50; // Short pulse duration in microseconds.
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// Preamble + sync
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const char* psync = "01010101010101010101010101010110";
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const char* p = psync;
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while(*p) {
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raw_samples_add_or_update(samples, *p == '1', te);
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p++;
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}
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// Data, 9 bytes
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uint8_t data[9] = {0};
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unsigned int raw_pressure = fieldset->fields[1]->fvalue * 4 / 3;
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data[0] = fieldset->fields[3]->uvalue << 2; // Flags
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data[0] |= (raw_pressure >> 8) & 3; // Pressure kpa high 2 bits
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data[1] = raw_pressure & 0xff; // Pressure kpa low 8 bits
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data[2] = fieldset->fields[2]->value + 30; // Temperature C
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memcpy(data + 3, fieldset->fields[0]->bytes, 6); // ID, 24 bits.
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data[6] = fieldset->fields[4]->bytes[0]; // Unknown 1
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data[7] = fieldset->fields[5]->bytes[0]; // Unknown 2
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data[8] = crc8(data, 8, 0, 7);
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// Generate Manchester code for each bit
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for(uint32_t j = 0; j < 9 * 8; j++) {
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if(bitmap_get(data, sizeof(data), j)) {
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raw_samples_add_or_update(samples, true, te);
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raw_samples_add_or_update(samples, false, te);
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} else {
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raw_samples_add_or_update(samples, false, te);
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raw_samples_add_or_update(samples, true, te);
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}
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}
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}
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ProtoViewDecoder RenaultTPMSDecoder = {
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.name = "Renault TPMS",
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.decode = decode,
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.get_fields = get_fields,
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.build_message = build_message};
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