mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2024-12-13 19:54:39 +00:00
95f7eda9c5
Several old bugs squashed. On the APRS side, most notably, SSID numbers where shifted left twice, instead of once, and bits 5,6 where not properly set. On AX.25 side, the bit stuffing part of the encoder was not placing the zero bit on the right place. Finally, I changed APRS icon from ORANGE to GREEN, since even this may be a simple app, now it's doing its work as intended.
135 lines
2.8 KiB
C++
135 lines
2.8 KiB
C++
/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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* Copyright (C) 2017 Furrtek
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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 "ax25.hpp"
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#include "portapack_shared_memory.hpp"
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namespace ax25 {
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void AX25Frame::make_extended_field(char * const data, size_t length) {
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size_t i = 0;
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for (i = 0; i < length - 1; i++)
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add_data(data[i] << 1);
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add_data((data[i] << 1) | 1);
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}
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void AX25Frame::NRZI_add_bit(const uint32_t bit) {
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if (!bit)
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current_bit ^= 1; // Zero: flip
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current_byte <<= 1;
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current_byte |= current_bit;
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bit_counter++;
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if (bit_counter == 8) {
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bit_counter = 0;
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*bb_data_ptr = current_byte;
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bb_data_ptr++;
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}
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}
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void AX25Frame::add_byte(uint8_t byte, bool is_flag, bool is_data)
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{
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bool bit;
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if (is_data)
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crc_ccitt.process_byte(byte);
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for (uint32_t i = 0; i < 8; i++)
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{
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bit = (byte >> i) & 1;
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NRZI_add_bit(bit);
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if (bit)
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{
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ones_counter++;
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if ((ones_counter == 5) && (!is_flag))
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{
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NRZI_add_bit(0);
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ones_counter = 0;
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}
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}
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else
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ones_counter = 0;
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}
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}
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void AX25Frame::flush()
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{
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if (bit_counter)
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*bb_data_ptr = current_byte << (8 - bit_counter); //euquiq: This was 7 but there are 8 bits
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};
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void AX25Frame::add_flag() {
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add_byte(AX25_FLAG, true, false);
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};
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void AX25Frame::add_data(uint8_t byte) {
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add_byte(byte, false, true);
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};
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void AX25Frame::add_checksum() {
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auto checksum = crc_ccitt.checksum();
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add_byte(checksum, false, false);
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add_byte(checksum >> 8, false, false);
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}
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void AX25Frame::make_ui_frame(char * const address, const uint8_t control,
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const uint8_t protocol, const std::string& info) {
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size_t i;
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bb_data_ptr = (uint16_t*)shared_memory.bb_data.data;
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memset(bb_data_ptr, 0, sizeof(shared_memory.bb_data.data));
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bit_counter = 0;
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current_bit = 0;
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current_byte = 0;
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ones_counter = 0;
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crc_ccitt.reset();
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add_flag();
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add_flag();
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add_flag();
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add_flag();
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make_extended_field(address, 14);
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add_data(control);
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add_data(protocol);
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for (i = 0; i < info.size(); i++)
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add_data(info[i]);
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add_checksum();
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add_flag();
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add_flag();
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flush();
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}
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} /* namespace ax25 */
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