portapack-mayhem/firmware/baseband/proc_afskrx.hpp

/*
 * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2016 Furrtek
 *
 * 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_AFSKRX_H__
#define __PROC_AFSKRX_H__

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

#include "dsp_decimate.hpp"
#include "dsp_demodulate.hpp"

#include "audio_output.hpp"

#include "fifo.hpp"
#include "message.hpp"

class AFSKRxProcessor : public BasebandProcessor {
   public:
    void execute(const buffer_c8_t& buffer) override;
    void on_message(const Message* const message) override;

   private:
    static constexpr size_t baseband_fs = 3072000;
    static constexpr size_t audio_fs = baseband_fs / 8 / 8 / 2;

    size_t samples_per_bit{};

    enum State {
        WAIT_START = 0,
        WAIT_STOP,
        RECEIVE
    };

    std::array<complex16_t, 512> dst{};
    const buffer_c16_t dst_buffer{
        dst.data(),
        dst.size()};
    std::array<float, 32> audio{};
    const buffer_f32_t audio_buffer{
        audio.data(),
        audio.size()};

    // Array size ok down to 375 bauds (24000 / 375)
    std::array<int32_t, 64> delay_line{0};

    dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0{};
    dsp::decimate::FIRC16xR16x32Decim8 decim_1{};
    dsp::decimate::FIRAndDecimateComplex channel_filter{};

    dsp::demodulate::FM demod{};

    AudioOutput audio_output{};

    State state{};
    size_t delay_line_index{};
    uint32_t bit_counter{0};
    uint32_t word_bits{0};
    uint32_t sample_bits{0};
    uint32_t phase{}, phase_inc{};
    int32_t sample_mixed{}, prev_mixed{}, sample_filtered{}, prev_filtered{};
    uint32_t word_length{};
    uint32_t word_mask{};
    uint32_t trigger_value{};

    bool configured{false};
    bool wait_start{};
    bool bit_value{};
    bool trigger_word{};
    bool triggered{};

    AFSKDataMessage data_message{false, 0};

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

    void configure(const AFSKRxConfigureMessage& message);
};

#endif /*__PROC_TPMS_H__*/