SyncPatternMonitor.h

Go to the documentation of this file.

// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
#ifndef ALICEO2_TPC_SYNCPATTERNMONITOR_H_
#define ALICEO2_TPC_SYNCPATTERNMONITOR_H_
 
#include <fairlogger/Logger.h>
#include <iosfwd>
#include <iomanip>
#include <array>
 
namespace o2
{
namespace tpc
{
 
 
class SyncPatternMonitor
{
 public:
  SyncPatternMonitor();
 
  SyncPatternMonitor(int sampa, int lowHigh);
 
  SyncPatternMonitor(const SyncPatternMonitor& other);
 
  ~SyncPatternMonitor() = default;
 
  void reset();
 
  short addSequence(const short hw0, const short hw1, const short hw2, const short hw3);
 
  short getPosition() { return mPatternFound ? mHwWithPattern : -1; };
 
  short getPatternA() const { return PATTERN_A; };
 
  short getPatternB() const { return PATTERN_B; };
 
  // Return first position to look for in whole pattern
  short getSyncStart() const { return SYNC_START; };
 
 private:
  const static short SYNC_START = 2;
  const static short PATTERN_A = 0x15;
  const static short PATTERN_B = 0x0A;
  static constexpr std::array<short, 32> SYNC_PATTERN{{PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B, PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B,
                                                       PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B, PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B,
                                                       PATTERN_A, PATTERN_A, PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B, PATTERN_B, PATTERN_B,
                                                       PATTERN_A, PATTERN_A, PATTERN_A, PATTERN_A, PATTERN_B, PATTERN_B, PATTERN_B, PATTERN_B}};
 
  void patternFound(const short hw);
 
  void checkWord(const short hw, const short pos);
 
  bool mPatternFound;     
  short mPosition;        
  short mHwWithPattern;   
  int mSampa;             
  int mLowHigh;           
  unsigned mCheckedWords; 
};
 
inline short SyncPatternMonitor::addSequence(const short hw0, const short hw1, const short hw2, const short hw3)
{
  checkWord(hw0, 1);
  checkWord(hw1, 2);
  checkWord(hw2, 3);
  checkWord(hw3, 0);
  return mPatternFound; //getPosition();
};
 
inline void SyncPatternMonitor::checkWord(const short hw, const short pos)
{
  ++mCheckedWords;
  if (hw == SYNC_PATTERN[mPosition]) {
    ++mPosition;
  } else if (!(mPosition == SYNC_START + 2 && hw == SYNC_PATTERN[mPosition - 1])) {
    mPosition = SYNC_START;
  }
  // Don't reset mPosition at the beginning to avoid missing of start of sync pattern in cases like
  //
  //
  //       ... A  A  A  B  B ...
  //
  //           ^  ^  ^
  // random A _|  |  |_ would trigger reset
  //              |
  //             real start
 
  if (mPosition == 32) {
    patternFound(pos);
  }
};
 
inline void SyncPatternMonitor::patternFound(const short hw)
{
  LOG(debug) << "SAMPA " << mSampa << " (" << ((mLowHigh == 0) ? " low" : "high") << "): "
             << "SYNC found at Position " << hw << " in checked half word #" << mCheckedWords;
  if (mPatternFound) {
    LOG(warning) << "SAMPA " << mSampa << " (" << ((mLowHigh == 0) ? " low" : "high") << "): "
                 << "SYNC was already found";
  }
  mPatternFound = true;
  mPosition = SYNC_START;
  mHwWithPattern = hw;
};
 
} // namespace tpc
} // namespace o2
#endif