mirror of
https://github.com/DarkFlippers/unleashed-firmware
synced 2024-12-18 16:53:45 +00:00
81 lines
3.1 KiB
C
81 lines
3.1 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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* Toyota tires TPMS. Usually 443.92 Mhz FSK (In Europe).
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*
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* Preamble + sync + 64 bits of data. ~48us short pulse length.
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*
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* The preamble + sync is something like:
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*
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* 10101010101 (preamble) + 001111[1] (sync)
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*
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* Note: the final [1] means that sometimes it is four 1s, sometimes
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* five, depending on the short pulse length detection and the exact
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* duration of the high long pulse. After the sync, a differential
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* Manchester encoded payload follows. However the Flipper's CC1101
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* often can't decode correctly the initial alternating pattern 101010101,
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* so what we do is to seek just the sync, that is "001111" or "0011111",
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* however we now that it must be followed by one differenitally encoded
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* bit, so we can use also the first symbol of data to force a more robust
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* detection, and look for one of the following:
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*
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* [001111]00
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* [0011111]00
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* [001111]01
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* [0011111]01
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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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if(numbits - 6 < 64 * 2)
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return false; /* Ask for 64 bit of data (each bit
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is two symbols in the bitmap). */
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char* sync[] = {"00111100", "001111100", "00111101", "001111101", NULL};
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int j;
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uint32_t off = 0;
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for(j = 0; sync[j]; j++) {
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off = bitmap_seek_bits(bits, numbytes, 0, numbits, sync[j]);
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if(off != BITMAP_SEEK_NOT_FOUND) {
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info->start_off = off;
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off += strlen(sync[j]) - 2;
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break;
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}
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}
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if(off == BITMAP_SEEK_NOT_FOUND) return false;
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FURI_LOG_E(TAG, "Toyota TPMS sync[%s] found", sync[j]);
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uint8_t raw[9];
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uint32_t decoded = convert_from_diff_manchester(raw, sizeof(raw), bits, numbytes, off, true);
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FURI_LOG_E(TAG, "Toyota TPMS decoded bits: %lu", decoded);
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if(decoded < 8 * 9) return false; /* Require the full 8 bytes. */
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if(crc8(raw, 8, 0x80, 7) != raw[8]) return false; /* Require sane CRC. */
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/* We detected a valid signal. However now info->start_off is actually
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* pointing to the sync part, not the preamble of alternating 0 and 1.
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* Protoview decoders get called with some space to the left, in order
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* for the decoder itself to fix the signal if neeeded, so that its
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* logical representation will be more accurate and better to save
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* and retransmit. */
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if(info->start_off >= 12) {
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info->start_off -= 12;
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bitmap_set_pattern(bits, numbytes, info->start_off, "010101010101");
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}
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info->pulses_count = (off + 8 * 9 * 2) - info->start_off;
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float psi = (float)((raw[4] & 0x7f) << 1 | raw[5] >> 7) * 0.25 - 7;
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int temp = ((raw[5] & 0x7f) << 1 | raw[6] >> 7) - 40;
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fieldset_add_bytes(info->fieldset, "Tire ID", raw, 4 * 2);
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fieldset_add_float(info->fieldset, "Pressure psi", psi, 2);
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fieldset_add_int(info->fieldset, "Temperature C", temp, 8);
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return true;
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}
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ProtoViewDecoder ToyotaTPMSDecoder =
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{.name = "Toyota TPMS", .decode = decode, .get_fields = NULL, .build_message = NULL};
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