portapack-mayhem/firmware/baseband/proc_nrfrx.cpp

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/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2016 Furrtek
* Copyright (C) 2020 Shao
*
* 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_nrfrx.hpp"
#include "portapack_shared_memory.hpp"
#include "event_m4.hpp"
void NRFRxProcessor::execute(const buffer_c8_t& buffer) {
if (!configured) return;
// FM demodulation
const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
feed_channel_stats(decim_0_out);
auto audio_oversampled = demod.execute(decim_0_out, work_audio_buffer);
// Audio signal processing
for (size_t c = 0; c < audio_oversampled.count; c++) {
int g_srate = 4; // 4 for 250KPS
// int g_srate = 1; //1 for 1MPS, not working yet
int32_t current_sample = audio_oversampled.p[c]; // if I directly use this, some results can pass crc but not correct.
rb_head++;
rb_head = (rb_head) % RB_SIZE;
rb_buf[rb_head] = current_sample;
skipSamples = skipSamples - 1;
if (skipSamples < 1) {
int32_t threshold_tmp = 0;
for (int c = 0; c < 8 * g_srate; c++) {
threshold_tmp = threshold_tmp + (int32_t)rb_buf[(rb_head + c) % RB_SIZE];
}
g_threshold = (int32_t)threshold_tmp / (8 * g_srate);
int transitions = 0;
if (rb_buf[(rb_head + 9 * g_srate) % RB_SIZE] > g_threshold) {
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + c * g_srate) % RB_SIZE] > rb_buf[(rb_head + (c + 1) * g_srate) % RB_SIZE])
transitions = transitions + 1;
}
} else {
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + c * g_srate) % RB_SIZE] < rb_buf[(rb_head + (c + 1) * g_srate) % RB_SIZE])
transitions = transitions + 1;
}
}
bool packet_detected = false;
// if ( transitions==4 && abs(g_threshold)<15500)
if (transitions == 4 && abs(g_threshold) < 15500) {
int packet_length = 0;
uint8_t tmp_buf[10];
uint8_t packet_data[500];
uint8_t packet_packed[50];
uint16_t pcf;
uint32_t packet_crc;
uint32_t calced_crc;
uint64_t packet_addr_l;
/* extract address */
packet_addr_l = 0;
for (int t = 0; t < 5; t++) {
bool current_bit;
uint8_t byte = 0;
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + (1 * 8 + t * 8 + c) * g_srate) % RB_SIZE] > g_threshold)
current_bit = true;
else
current_bit = false;
byte |= current_bit << (7 - c);
}
tmp_buf[t] = byte;
}
for (int t = 0; t < 5; t++) packet_addr_l |= ((uint64_t)tmp_buf[t]) << (4 - t) * 8;
// channel_number = 26;
/* extract pcf */
for (int t = 0; t < 2; t++) {
bool current_bit;
uint8_t byte = 0;
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + (6 * 8 + t * 8 + c) * g_srate) % RB_SIZE] > g_threshold)
current_bit = true;
else
current_bit = false;
byte |= current_bit << (7 - c);
}
tmp_buf[t] = byte;
}
pcf = tmp_buf[0] << 8 | tmp_buf[1];
pcf >>= 7;
/* extract packet length, avoid excessive length packets */
if (packet_length == 0)
packet_length = (int)pcf >> 3;
if (packet_length > 32)
packet_detected = false;
/* extract data */
for (int t = 0; t < packet_length; t++) {
bool current_bit;
uint8_t byte = 0;
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + (6 * 8 + 9 + t * 8 + c) * g_srate) % RB_SIZE] > g_threshold)
current_bit = true;
else
current_bit = false;
byte |= current_bit << (7 - c);
}
packet_data[t] = byte;
}
/* Prepare packed bit stream for CRC calculation */
uint64_t packet_header = packet_addr_l;
packet_header <<= 9;
packet_header |= pcf;
for (int c = 0; c < 7; c++) {
packet_packed[c] = (packet_header >> ((6 - c) * 8)) & 0xFF;
}
for (int c = 0; c < packet_length; c++) {
packet_packed[c + 7] = packet_data[c];
}
/* calculate packet crc */
const uint8_t* data = packet_packed;
size_t data_len = 7 + packet_length;
bool bit;
uint8_t cc;
uint_fast16_t crc = 0x3C18;
while (data_len--) {
cc = *data++;
for (uint8_t i = 0x80; i > 0; i >>= 1) {
bit = crc & 0x8000;
if (cc & i) {
bit = !bit;
}
crc <<= 1;
if (bit) {
crc ^= 0x1021;
}
}
crc &= 0xffff;
}
calced_crc = (uint16_t)(crc & 0xffff);
/* extract crc */
for (int t = 0; t < 2; t++) {
bool current_bit;
uint8_t byte = 0;
for (int c = 0; c < 8; c++) {
if (rb_buf[(rb_head + ((6 + packet_length) * 8 + 9 + t * 8 + c) * g_srate) % RB_SIZE] > g_threshold)
current_bit = true;
else
current_bit = false;
byte |= current_bit << (7 - c);
}
tmp_buf[t] = byte;
}
packet_crc = tmp_buf[0] << 8 | tmp_buf[1];
/* NRF24L01+ packet found, dump information */
// if (packet_addr_l==0xE7E7E7E7)
if (packet_crc == calced_crc) {
data_message.is_data = false;
data_message.value = 'A';
shared_memory.application_queue.push(data_message);
data_message.is_data = true;
data_message.value = packet_addr_l;
shared_memory.application_queue.push(data_message);
for (int c = 0; c < 7; c++) {
data_message.is_data = true;
data_message.value = packet_addr_l >> 8;
shared_memory.application_queue.push(data_message);
}
/*data_message.is_data = true;
data_message.value = packet_addr_l;
shared_memory.application_queue.push(data_message);
data_message.is_data = true;
data_message.value = packet_addr_l >> 8;
shared_memory.application_queue.push(data_message);*/
data_message.is_data = false;
data_message.value = 'B';
shared_memory.application_queue.push(data_message);
for (int c = 0; c < packet_length; c++) {
data_message.is_data = true;
data_message.value = packet_data[c];
shared_memory.application_queue.push(data_message);
}
data_message.is_data = false;
data_message.value = 'C';
shared_memory.application_queue.push(data_message);
packet_detected = true;
} else
packet_detected = false;
}
if (packet_detected) {
skipSamples = 20;
}
}
}
}
void NRFRxProcessor::on_message(const Message* const message) {
if (message->id == Message::ID::NRFRxConfigure)
configure(*reinterpret_cast<const NRFRxConfigureMessage*>(message));
}
void NRFRxProcessor::configure(const NRFRxConfigureMessage& message) {
(void)message; // avoir unused warning
decim_0.configure(taps_200k_wfm_decim_0.taps, 33554432);
decim_1.configure(taps_200k_wfm_decim_1.taps, 131072);
demod.configure(audio_fs, 5000);
configured = true;
}
int main() {
EventDispatcher event_dispatcher{std::make_unique<NRFRxProcessor>()};
event_dispatcher.run();
return 0;
}