portapack-mayhem/firmware/baseband/proc_mictx.cpp

/*
 * 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.
 */

#include "proc_mictx.hpp"
#include "portapack_shared_memory.hpp"
#include "sine_table_int8.hpp"
#include "event_m4.hpp"

#include <cstdint>

void MicTXProcessor::execute(const buffer_c8_t& buffer){

	// This is called at 1536000/2048 = 750Hz
	
	if (!configured) return;
	
	audio_input.read_audio_buffer(audio_buffer);

	for (size_t i = 0; i<buffer.count; i++) {
		
		sample = audio_buffer.p[i >> 6] >> 8;
		
		power += (sample < 0) ? -sample : sample;
		
		if (!as) {
			as = divider;
			level_message.value = power / (divider / 4);
			shared_memory.application_queue.push(level_message);
			power = 0;
		} else {
			as--;
		}
		
		if (ctcss_enabled) {
			ctcss_sample = sine_table_i8[(ctcss_phase & 0xFF000000U) >> 24];
			sample_mixed = ((sample * 205) + (ctcss_sample * 50)) / 256;	// ~20%
			ctcss_phase += ctcss_phase_inc;
		} else {
			sample_mixed = sample;
		}
		
		// FM
		delta = sample_mixed * fm_delta;
		
		phase += delta;
		sphase = phase + (64 << 24);

		re = (sine_table_i8[(sphase & 0xFF000000U) >> 24]);
		im = (sine_table_i8[(phase & 0xFF000000U) >> 24]);
		
		buffer.p[i] = {re, im};
	}
}

void MicTXProcessor::on_message(const Message* const msg) {
	const auto message = *reinterpret_cast<const AudioTXConfigMessage*>(msg);
	
	switch(msg->id) {
		case Message::ID::AudioTXConfig:
			fm_delta = message.fm_delta * (0xFFFFFFULL / 1536000);
			divider = message.divider;
			ctcss_enabled = message.ctcss_enabled;
			ctcss_phase_inc = message.ctcss_phase_inc;

			configured = true;
			break;

		default:
			break;
	}
}

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