mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2024-12-14 20:18:13 +00:00
118 lines
3.6 KiB
C++
118 lines
3.6 KiB
C++
/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include "proc_fsk.hpp"
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#include "portapack_shared_memory.hpp"
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#include "i2s.hpp"
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using namespace lpc43xx;
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FSKProcessor::FSKProcessor(
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MessageHandlerMap& message_handlers
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) : message_handlers(message_handlers)
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{
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message_handlers.register_handler(Message::ID::FSKConfiguration,
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[this](const Message* const p) {
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auto m = reinterpret_cast<const FSKConfigurationMessage*>(p);
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this->configure(m->configuration);
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}
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);
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}
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FSKProcessor::~FSKProcessor() {
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message_handlers.unregister_handler(Message::ID::FSKConfiguration);
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}
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void FSKProcessor::configure(const FSKConfiguration new_configuration) {
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// TODO: Matched filter characteristics are hard-coded for the moment. YUCK!
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decimator.set_decimation_factor(ChannelDecimator::DecimationFactor::By16);
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channel_filter.configure(channel_filter_taps.taps, 8);
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mf.configure(baseband::ais::rrc_taps_128_decim_4_p, 1);
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clock_recovery.configure(new_configuration.symbol_rate * 2, new_configuration.symbol_rate, { 0.0555f });
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packet_builder.configure(
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{ new_configuration.access_code, new_configuration.access_code_length, new_configuration.access_code_tolerance },
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{ new_configuration.unstuffing_pattern, new_configuration.unstuffing_length }
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);
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}
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void FSKProcessor::execute(buffer_c8_t buffer) {
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/* 2.4576MHz, 2048 samples */
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auto decimator_out = decimator.execute(buffer);
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/* 153.6kHz, 128 samples */
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const buffer_c16_t work_baseband_buffer {
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(complex16_t*)decimator_out.p,
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decimator_out.count
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};
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/* 153.6kHz complex<int16_t>[128]
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* -> FIR filter, <?kHz (?fs) pass, gain 1.0
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* -> 19.2kHz int16_t[16] */
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auto channel = channel_filter.execute(decimator_out, work_baseband_buffer);
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/* 76.8kHz, 64 samples */
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feed_channel_stats(channel);
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/* No spectrum display while FSK decoding.
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feed_channel_spectrum(
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channel,
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decimator_out.sampling_rate * channel_filter_taps.pass_frequency_normalized,
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decimator_out.sampling_rate * channel_filter_taps.stop_frequency_normalized
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);
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*/
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// 76.8k
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// TODO: Factor out this hidden decimation magic.
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for(size_t i=0; i<channel.count; i++) {
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// TODO: No idea why implicit cast int16_t->float is not allowed.
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const std::complex<float> sample {
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static_cast<float>(channel.p[i].real()),
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static_cast<float>(channel.p[i].imag())
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};
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if( mf.execute_once(sample) ) {
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clock_recovery(mf.get_output());
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}
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}
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i2s::i2s0::tx_mute();
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}
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void FSKProcessor::consume_symbol(
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const float raw_symbol
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) {
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const uint_fast8_t sliced_symbol = (raw_symbol >= 0.0f) ? 1 : 0;
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const auto decoded_symbol = nrzi_decode(sliced_symbol);
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packet_builder.execute(decoded_symbol);
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}
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void FSKProcessor::payload_handler(
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const std::bitset<1024>& payload,
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const size_t bits_received
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) {
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FSKPacketMessage message;
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message.packet.payload = payload;
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message.packet.bits_received = bits_received;
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shared_memory.application_queue.push(message);
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}
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