/* * Copyright (C) 2017 Jared Boone, ShareBrained Technology, Inc. * Copyright (C) 2019 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 "rfm69.hpp" #include "crc.hpp" #include "portapack_shared_memory.hpp" uint32_t RFM69::gen_frame(std::vector<uint8_t>& payload) { CRC<16> crc { 0x1021, 0x1D0F, 0xFFFF }; std::vector<uint8_t> frame { }; uint8_t byte_out = 0; // Preamble // Really is 0xAA but the RFM69 skips the very last bit (bug ?) // so the whole preamble is shifted right to simulate that frame.insert(frame.begin(), num_preamble_, 0x55); // Sync word frame.push_back(sync_word_ >> 8); frame.push_back(sync_word_ & 0xFF); // Payload length payload.insert(payload.begin(), payload.size()); crc.process_bytes(payload.data(), payload.size()); if (CRC_) { payload.push_back(crc.checksum() >> 8); payload.push_back(crc.checksum() & 0xFF); } // Manchester-encode payload if (manchester_) { for (auto byte : payload) { for (uint32_t b = 0; b < 8; b++) { byte_out <<= 2; if (byte & 0x80) byte_out |= 0b10; else byte_out |= 0b01; if ((b & 3) == 3) frame.push_back(byte_out); byte <<= 1; } } } else { frame.insert(frame.end(), payload.begin(), payload.end()); } memcpy(shared_memory.bb_data.data, frame.data(), frame.size()); // Copy for baseband return frame.size(); }