DStarRX.h

/*
 *   Copyright (C) 2015,2016,2017,2020 by Jonathan Naylor G4KLX
 *
 *   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 of the License, 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; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "Config.h"

#if defined(MODE_DSTAR)

#if !defined(DSTARRX_H)
#define  DSTARRX_H

#include "DStarDefines.h"

enum DSRX_STATE {
  DSRXS_NONE,
  DSRXS_HEADER,
  DSRXS_DATA
};

class CDStarRX {
public:
  CDStarRX();

  void samples(const q15_t* samples, const uint16_t* rssi, uint8_t length);

  void reset();

private:
  DSRX_STATE   m_rxState;
  uint64_t     m_bitBuffer[DSTAR_RADIO_SYMBOL_LENGTH];
  q15_t        m_headerBuffer[DSTAR_FEC_SECTION_LENGTH_SAMPLES + 2U * DSTAR_RADIO_SYMBOL_LENGTH];
  q15_t        m_dataBuffer[DSTAR_DATA_LENGTH_SAMPLES];
  uint16_t     m_bitPtr;
  uint16_t     m_headerPtr;
  uint16_t     m_dataPtr;
  uint16_t     m_startPtr;
  uint16_t     m_syncPtr;
  uint16_t     m_minSyncPtr;
  uint16_t     m_maxSyncPtr;
  q31_t        m_maxFrameCorr;
  q31_t        m_maxDataCorr;
  uint16_t     m_frameCount;
  uint8_t      m_countdown;
  unsigned int m_mar;
  int          m_pathMetric[4U];
  unsigned int m_pathMemory0[42U];
  unsigned int m_pathMemory1[42U];
  unsigned int m_pathMemory2[42U];
  unsigned int m_pathMemory3[42U];
  uint8_t      m_fecOutput[42U];
  uint32_t     m_rssiAccum;
  uint16_t     m_rssiCount;
  
  void    processNone(q15_t sample);
  void    processHeader(q15_t sample);
  void    processData();
  bool    correlateFrameSync();
  bool    correlateDataSync();
  void    samplesToBits(const q15_t* inBuffer, uint16_t start, uint16_t count, uint8_t* outBuffer, uint16_t limit);
  void    writeRSSIHeader(unsigned char* header);
  void    writeRSSIData(unsigned char* data);
  bool    rxHeader(uint8_t* in, uint8_t* out);
  void    acs(int* metric);
  void    viterbiDecode(int* data);
  void    traceBack();
  bool    checksum(const uint8_t* header) const;
};

#endif

#endif