/* * SEE ADDITIONAL COPYRIGHT ATTRIBUTION BELOW * © 2024 Chris Harlow * All rights reserved. * * This file is part of DCC-EX * * This 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 3 of the License, or * (at your option) any later version. * * It 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 CommandStation. If not, see . */ /** Sections of this code (the decode table constants) * are taken from openmrn under the following copyright. * * Copyright (c) 2014, Balazs Racz * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. **/ #include "Railcom.h" #include "FSH.h" /** Table for 8-to-6 decoding of railcom data. This table can be indexed by the * 8-bit value read from the railcom channel, and the return value will be * either a 6-bit number, or one of the defined Railcom constrantrs. If the * value is invalid, the INV constant is returned. */ // These values appear in the railcom_decode table to mean special symbols. static constexpr uint8_t // highest valid 6-bit value MAX_VALID = 0x3F, /// invalid value (not conforming to the 4bit weighting requirement) INV = 0xff, /// Railcom ACK; the decoder received the message ok. NOTE: There are /// two codepoints that map to this. ACK = 0xfe, /// The decoder rejected the packet. NACK = 0xfd, /// The decoder is busy; send the packet again. This is typically /// returned when a POM CV write is still pending; the caller must /// re-try sending the packet later. RCBUSY = 0xfc, /// Reserved for future expansion. RESVD1 = 0xfb, /// Reserved for future expansion. RESVD2 = 0xfa; const uint8_t HIGHFLASH decode[256] = // 0|8 1|9 2|a 3|b 4|c 5|d 6|e 7|f { INV, INV, INV, INV, INV, INV, INV, INV, // 0 INV, INV, INV, INV, INV, INV, INV, ACK, // 0 INV, INV, INV, INV, INV, INV, INV, 0x33, // 1 INV, INV, INV, 0x34, INV, 0x35, 0x36, INV, // 1 INV, INV, INV, INV, INV, INV, INV, 0x3A, // 2 INV, INV, INV, 0x3B, INV, 0x3C, 0x37, INV, // 2 INV, INV, INV, 0x3F, INV, 0x3D, 0x38, INV, // 3 INV, 0x3E, 0x39, INV, NACK, INV, INV, INV, // 3 INV, INV, INV, INV, INV, INV, INV, 0x24, // 4 INV, INV, INV, 0x23, INV, 0x22, 0x21, INV, // 4 INV, INV, INV, 0x1F, INV, 0x1E, 0x20, INV, // 5 INV, 0x1D, 0x1C, INV, 0x1B, INV, INV, INV, // 5 INV, INV, INV, 0x19, INV, 0x18, 0x1A, INV, // 6 INV, 0x17, 0x16, INV, 0x15, INV, INV, INV, // 6 INV, 0x25, 0x14, INV, 0x13, INV, INV, INV, // 7 0x32, INV, INV, INV, INV, INV, INV, INV, // 7 INV, INV, INV, INV, INV, INV, INV, RESVD2, // 8 INV, INV, INV, 0x0E, INV, 0x0D, 0x0C, INV, // 8 INV, INV, INV, 0x0A, INV, 0x09, 0x0B, INV, // 9 INV, 0x08, 0x07, INV, 0x06, INV, INV, INV, // 9 INV, INV, INV, 0x04, INV, 0x03, 0x05, INV, // a INV, 0x02, 0x01, INV, 0x00, INV, INV, INV, // a INV, 0x0F, 0x10, INV, 0x11, INV, INV, INV, // b 0x12, INV, INV, INV, INV, INV, INV, INV, // b INV, INV, INV, RESVD1, INV, 0x2B, 0x30, INV, // c INV, 0x2A, 0x2F, INV, 0x31, INV, INV, INV, // c INV, 0x29, 0x2E, INV, 0x2D, INV, INV, INV, // d 0x2C, INV, INV, INV, INV, INV, INV, INV, // d INV, RCBUSY, 0x28, INV, 0x27, INV, INV, INV, // e 0x26, INV, INV, INV, INV, INV, INV, INV, // e ACK, INV, INV, INV, INV, INV, INV, INV, // f INV, INV, INV, INV, INV, INV, INV, INV, // f }; /// Packet identifiers from Mobile Decoders. enum RailcomMobilePacketId { RMOB_POM = 0, RMOB_ADRHIGH = 1, RMOB_ADRLOW = 2, RMOB_EXT = 3, RMOB_DYN = 7, RMOB_XPOM0 = 8, RMOB_XPOM1 = 9, RMOB_XPOM2 = 10, RMOB_XPOM3 = 11, RMOB_SUBID = 12, RMOB_LOGON_ASSIGN_FEEDBACK = 13, RMOB_LOGON_ENABLE_FEEDBACK = 15, }; Railcom::Railcom() { haveHigh=false; haveLow=false; packetsWithNoData=0; } /* returns -1: Call again next packet 0: No loco on track >0: loco id */ int16_t Railcom::getChannel1Loco(uint8_t * inbound) { auto v1=GETHIGHFLASH(decode,inbound[0]); auto v2=GETHIGHFLASH(decode,inbound[1]); auto packet=(v1<<6) | v2; // packet is 12 bits TTTTDDDDDDDD auto type=packet>>8; auto data= packet & 0xFF; if (type==RMOB_ADRHIGH) { holdoverHigh=data; haveHigh=true; packetsWithNoData=0; } else if (type==RMOB_ADRLOW) { holdoverLow=data; haveLow=true; packetsWithNoData=0; } else if (type==RMOB_EXT) { return -1; /* ignore*/ } else { if (packetsWithNoData>MAX_WAIT_FOR_GLITCH) { haveHigh=false; haveLow=false; return 0; // treat as no loco } packetsWithNoData++; return -1; // need more data } if (haveHigh && haveLow) return ((holdoverHigh<<8)| holdoverLow); return -1; // call again, need next packet }