mayhem-firmware/firmware/baseband/proc_btlerx.cpp

/*
 * 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_btlerx.hpp"
#include "portapack_shared_memory.hpp"

#include "event_m4.hpp"

void BTLERxProcessor::execute(const buffer_c8_t& buffer) {
    if (!configured) return;

    // FM demodulation

    /*const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
        const auto channel = decim_1.execute(decim_0_out, dst_buffer);

        feed_channel_stats(channel);

        auto audio_oversampled = demod.execute(channel, work_audio_buffer);*/

    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);

    /*std::fill(spectrum.begin(), spectrum.end(), 0);
        for(size_t i=0; i<spectrum.size(); i++) {
                spectrum[i] += buffer.p[i];
        }
        const buffer_c16_t buffer_c16 {spectrum.data(),spectrum.size(),buffer.sampling_rate};
        feed_channel_stats(buffer_c16);

        auto audio_oversampled = demod.execute(buffer_c16, work_audio_buffer);*/
    // Audio signal processing
    for (size_t c = 0; c < audio_oversampled.count; c++) {
        /*const int32_t sample_int = audio_oversampled.p[c] * 32768.0f;
                int32_t current_sample = __SSAT(sample_int, 16);
                current_sample /= 128;*/

        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; c++) {
                threshold_tmp = threshold_tmp + (int32_t)rb_buf[(rb_head + c) % RB_SIZE];
            }
            g_threshold = (int32_t)threshold_tmp / 8;

            int transitions = 0;
            if (rb_buf[(rb_head + 9) % RB_SIZE] > g_threshold) {
                for (int c = 0; c < 8; c++) {
                    if (rb_buf[(rb_head + c) % RB_SIZE] > rb_buf[(rb_head + c + 1) % RB_SIZE])
                        transitions = transitions + 1;
                }
            } else {
                for (int c = 0; c < 8; c++) {
                    if (rb_buf[(rb_head + c) % RB_SIZE] < rb_buf[(rb_head + c + 1) % RB_SIZE])
                        transitions = transitions + 1;
                }
            }

            bool packet_detected = false;
            // if ( transitions==4 && abs(g_threshold)<15500)
            if (transitions == 4) {
                uint8_t packet_data[500];
                int packet_length;
                uint32_t packet_crc;
                // uint32_t calced_crc; // NOTE: restore when CRC is passing
                uint64_t packet_addr_l;
                // uint32_t result; // NOTE: restore when CRC is passing
                uint8_t crc[3];
                uint8_t packet_header_arr[2];

                packet_addr_l = 0;
                for (int i = 0; i < 4; i++) {
                    bool current_bit;
                    uint8_t byte = 0;
                    for (int c = 0; c < 8; c++) {
                        if (rb_buf[(rb_head + (i + 1) * 8 + c) % RB_SIZE] > g_threshold)
                            current_bit = true;
                        else
                            current_bit = false;
                        byte |= current_bit << (7 - c);
                    }
                    uint8_t byte_temp = (uint8_t)(((byte * 0x0802LU & 0x22110LU) | (byte * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                    packet_addr_l |= ((uint64_t)byte_temp) << (8 * i);
                }

                channel_number = 38;

                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 + 5 * 8 + t * 8 + c) % RB_SIZE] > g_threshold)
                            current_bit = true;
                        else
                            current_bit = false;
                        byte |= current_bit << (7 - c);
                    }

                    packet_header_arr[t] = byte;
                }

                uint8_t byte_temp2 = (uint8_t)(((channel_number * 0x0802LU & 0x22110LU) | (channel_number * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                uint8_t lfsr_1 = byte_temp2 | 2;
                int header_length = 2;
                int header_counter = 0;
                while (header_length--) {
                    for (uint8_t i = 0x80; i; i >>= 1) {
                        if (lfsr_1 & 0x80) {
                            lfsr_1 ^= 0x11;
                            (packet_header_arr[header_counter]) ^= i;
                        }
                        lfsr_1 <<= 1;
                    }
                    header_counter = header_counter + 1;
                }

                if (packet_addr_l == 0x8E89BED6) {
                    uint8_t byte_temp3 = (uint8_t)(((packet_header_arr[1] * 0x0802LU & 0x22110LU) | (packet_header_arr[1] * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                    packet_length = byte_temp3 & 0x3F;

                } else {
                    packet_length = 0;
                }

                for (int t = 0; t < packet_length + 2 + 3; t++) {
                    bool current_bit;
                    uint8_t byte = 0;
                    for (int c = 0; c < 8; c++) {
                        if (rb_buf[(rb_head + 5 * 8 + t * 8 + c) % RB_SIZE] > g_threshold)
                            current_bit = true;
                        else
                            current_bit = false;
                        byte |= current_bit << (7 - c);
                    }

                    packet_data[t] = byte;
                }

                uint8_t byte_temp4 = (uint8_t)(((channel_number * 0x0802LU & 0x22110LU) | (channel_number * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                uint8_t lfsr_2 = byte_temp4 | 2;
                int pdu_crc_length = packet_length + 2 + 3;
                int pdu_crc_counter = 0;
                while (pdu_crc_length--) {
                    for (uint8_t i = 0x80; i; i >>= 1) {
                        if (lfsr_2 & 0x80) {
                            lfsr_2 ^= 0x11;
                            (packet_data[pdu_crc_counter]) ^= i;
                        }
                        lfsr_2 <<= 1;
                    }
                    pdu_crc_counter = pdu_crc_counter + 1;
                }

                if (packet_addr_l == 0x8E89BED6) {
                    crc[0] = crc[1] = crc[2] = 0x55;
                } else {
                    crc[0] = crc[1] = crc[2] = 0;
                }

                uint8_t v, t, d, crc_length;
                uint32_t crc_result = 0;
                crc_length = packet_length + 2;
                int counter = 0;
                while (crc_length--) {
                    uint8_t byte_temp5 = (uint8_t)(((packet_data[counter] * 0x0802LU & 0x22110LU) | (packet_data[counter] * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                    d = byte_temp5;
                    for (v = 0; v < 8; v++, d >>= 1) {
                        t = crc[0] >> 7;
                        crc[0] <<= 1;
                        if (crc[1] & 0x80) crc[0] |= 1;
                        crc[1] <<= 1;
                        if (crc[2] & 0x80) crc[1] |= 1;
                        crc[2] <<= 1;
                        if (t != (d & 1)) {
                            crc[2] ^= 0x5B;
                            crc[1] ^= 0x06;
                        }
                    }
                    counter = counter + 1;
                }
                for (v = 0; v < 3; v++) crc_result = (crc_result << 8) | crc[v];
                // calced_crc = crc_result; // NOTE: restore when CRC is passing

                packet_crc = 0;
                for (int c = 0; c < 3; c++) packet_crc = (packet_crc << 8) | packet_data[packet_length + 2 + c];

                if (packet_addr_l == 0x8E89BED6)
                // if (packet_crc==calced_crc) // NOTE: restore when CRC is passing
                {
                    uint8_t mac_data[6];
                    int counter = 0;
                    for (int i = 7; i >= 2; i--) {
                        uint8_t byte_temp6 = (uint8_t)(((packet_data[i] * 0x0802LU & 0x22110LU) | (packet_data[i] * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
                        // result = byte_temp6; // NOTE: restore when CRC is passing
                        mac_data[counter] = byte_temp6;
                        counter = counter + 1;
                    }

                    data_message.is_data = false;
                    data_message.value = 'A';
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[0];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[1];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[2];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[3];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[4];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = true;
                    data_message.value = mac_data[5];
                    shared_memory.application_queue.push(data_message);

                    data_message.is_data = false;
                    data_message.value = 'B';
                    shared_memory.application_queue.push(data_message);

                    packet_detected = true;
                } else
                    packet_detected = false;
            }

            if (packet_detected) {
                skipSamples = 20;
            }
        }
    }
}

void BTLERxProcessor::on_message(const Message* const message) {
    if (message->id == Message::ID::BTLERxConfigure)
        configure(*reinterpret_cast<const BTLERxConfigureMessage*>(message));
}

void BTLERxProcessor::configure(const BTLERxConfigureMessage& message) {
    (void)message;  // avoid warning
    decim_0.configure(taps_200k_wfm_decim_0.taps);
    decim_1.configure(taps_200k_wfm_decim_1.taps);
    demod.configure(audio_fs, 5000);

    configured = true;
}

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