portapack-mayhem/firmware/baseband/proc_ert.hpp

/*
 * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2023 Mark Thompson
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef __PROC_ERT_H__
#define __PROC_ERT_H__

#include "baseband_processor.hpp"
#include "baseband_thread.hpp"
#include "rssi_thread.hpp"

#include "channel_decimator.hpp"

#include "clock_recovery.hpp"
#include "symbol_coding.hpp"
#include "packet_builder.hpp"
#include "baseband_packet.hpp"

#include "message.hpp"

#include <cstdint>
#include <cstddef>
#include <bitset>

// ''.join(['%d%d' % (c, 1-c) for c in map(int, bin(0x1f2a60)[2:].zfill(21))])
constexpr uint64_t scm_preamble_and_sync_manchester{0b101010101001011001100110010110100101010101};
constexpr size_t scm_preamble_and_sync_length{42 - 10};
constexpr size_t scm_payload_length_max{150};

// ''.join(['%d%d' % (c, 1-c) for c in map(int, bin(0x16a3)[2:].zfill(16))])
constexpr uint64_t scmplus_preamble_and_sync_manchester{0b01010110011010011001100101011010};
constexpr size_t scmplus_preamble_and_sync_length{32 - 0};
constexpr size_t scmplus_payload_length_max{224};

// ''.join(['%d%d' % (c, 1-c) for c in map(int, bin(0x555516a3)[2:].zfill(32))])
constexpr uint64_t idm_preamble_and_sync_manchester{0b0110011001100110011001100110011001010110011010011001100101011010};
constexpr size_t idm_preamble_and_sync_length{64 - 16};
constexpr size_t idm_payload_length_max{1408};

class ERTProcessor : public BasebandProcessor {
   public:
    void execute(const buffer_c8_t& buffer) override;

   private:
    const uint32_t baseband_sampling_rate = 4194304;
    const size_t decimation = 1;
    const float symbol_rate = 32768;

    const uint32_t channel_sampling_rate = baseband_sampling_rate / decimation;
    const size_t samples_per_symbol = channel_sampling_rate / symbol_rate;
    const float clock_recovery_rate = symbol_rate * 2;

    clock_recovery::ClockRecovery<clock_recovery::FixedErrorFilter> clock_recovery{
        clock_recovery_rate,
        symbol_rate,
        {1.0f / 18.0f},
        [this](const float symbol) { this->consume_symbol(symbol); }};

    PacketBuilder<BitPattern, NeverMatch, FixedLength> scm_builder{
        {scm_preamble_and_sync_manchester, scm_preamble_and_sync_length, 1},
        {},
        {scm_payload_length_max},
        [this](const baseband::Packet& packet) {
            this->scm_handler(packet);
        }};

    PacketBuilder<BitPattern, NeverMatch, FixedLength> scmplus_builder{
        {scmplus_preamble_and_sync_manchester, scmplus_preamble_and_sync_length, 1},
        {},
        {scmplus_payload_length_max},
        [this](const baseband::Packet& packet) {
            this->scmplus_handler(packet);
        }};

    PacketBuilder<BitPattern, NeverMatch, FixedLength> idm_builder{
        {idm_preamble_and_sync_manchester, idm_preamble_and_sync_length, 1},
        {},
        {idm_payload_length_max},
        [this](const baseband::Packet& packet) {
            this->idm_handler(packet);
        }};

    void consume_symbol(const float symbol);
    void scm_handler(const baseband::Packet& packet);
    void scmplus_handler(const baseband::Packet& packet);
    void idm_handler(const baseband::Packet& packet);

    float sum_half_period[2];
    float sum_period[3];
    float manchester[3];

    const size_t average_window{2048};
    int32_t average_i{0};
    int32_t average_q{0};
    size_t average_count{0};
    float offset_i{0.0f};
    float offset_q{0.0f};

    /* NB: Threads should be the last members in the class definition. */
    BasebandThread baseband_thread{baseband_sampling_rate, this, baseband::Direction::Receive};
    RSSIThread rssi_thread{};

    float abs(const complex8_t& v);
};

#endif /*__PROC_ERT_H__*/