portapack-mayhem/firmware/baseband/proc_ais.cpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * 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.
 */

#include "proc_ais.hpp"

#include "portapack_shared_memory.hpp"

#include "dsp_fir_taps.hpp"

#include "event_m4.hpp"

AISProcessor::AISProcessor() {
    decim_0.configure(taps_11k0_decim_0.taps, 33554432);
    decim_1.configure(taps_11k0_decim_1.taps, 131072);
    baseband_thread.start();
}

void AISProcessor::execute(const buffer_c8_t& buffer) {
    /* 2.4576MHz, 2048 samples */

    const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
    const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
    const auto decimator_out = decim_1_out;

    /* 38.4kHz, 32 samples */
    feed_channel_stats(decimator_out);

    for (size_t i = 0; i < decimator_out.count; i++) {
        if (mf.execute_once(decimator_out.p[i])) {
            clock_recovery(mf.get_output());
        }
    }
}

void AISProcessor::consume_symbol(
    const float raw_symbol) {
    const uint_fast8_t sliced_symbol = (raw_symbol >= 0.0f) ? 1 : 0;
    const auto decoded_symbol = nrzi_decode(sliced_symbol);

    packet_builder.execute(decoded_symbol);
}

void AISProcessor::payload_handler(
    const baseband::Packet& packet) {
    const AISPacketMessage message{packet};
    shared_memory.application_queue.push(message);
}

int main() {
    EventDispatcher event_dispatcher{std::make_unique<AISProcessor>()};
    event_dispatcher.run();
    return 0;
}