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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [sysc/] [include/] [TapStateMachine.h] - Blame information for rev 178

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// ----------------------------------------------------------------------------
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// The TAP state machine: definition
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// Copyright (C) 2009  Embecosm Limited <info@embecosm.com>
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// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
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// This file is part of the Embecosm cycle accurate SystemC JTAG library.
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// This program is free software: you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or (at your
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// option) any later version.
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
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// License for more details.
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// You should have received a copy of the GNU Lesser General Public License
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// along with this program.  If not, see <http://www.gnu.org/licenses/>.
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// ----------------------------------------------------------------------------
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// $Id$
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#ifndef TAP_STATE_MACHINE__H
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#define TAP_STATE_MACHINE__H
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//! Enumeration of all the states in the TAP state machine.
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//! Last entry is not a state, but a marker of the number of states. Useful
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//! for state transition matrices.
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enum TapState {
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  TAP_TEST_LOGIC_RESET =  0,
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  TAP_RUN_TEST_IDLE    =  1,
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  TAP_SELECT_DR_SCAN   =  2,
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  TAP_CAPTURE_DR       =  3,
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  TAP_SHIFT_DR         =  4,
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  TAP_EXIT1_DR         =  5,
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  TAP_PAUSE_DR         =  6,
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  TAP_EXIT2_DR         =  7,
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  TAP_UPDATE_DR        =  8,
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  TAP_SELECT_IR_SCAN   =  9,
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  TAP_CAPTURE_IR       = 10,
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  TAP_SHIFT_IR         = 11,
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  TAP_EXIT1_IR         = 12,
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  TAP_PAUSE_IR         = 13,
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  TAP_EXIT2_IR         = 14,
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  TAP_UPDATE_IR        = 15,
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  TAP_SIZE             = 16
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};      // enum TapState
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//! Textual representation of all the TAP states.
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//! Provided for debugging purposes
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static const char *tapStateNames[TAP_SIZE] = {
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  "Test-Logic-Reset",
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  "Run-Test/Idle",
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  "Select-DR-Scan",
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  "Capture-DR",
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  "Shift-DR",
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  "Exit1-DR",
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  "Pause-DR",
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  "Exit2-DR",
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  "Update-DR",
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  "Select-IR-Scan",
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  "Capture-IR",
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  "Shift-IR",
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  "Exit1-IR",
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  "Pause-IR",
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  "Exit2-IR",
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  "Update-IR"
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};      // tapStateNames
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//! TAP state machine
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//! Tracks the state of the TAP. This should mirror the state of the TAP in
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//! the connected HW.
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//! The state machine is created in the reset condition, but in truth we
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//! cannot know what the state is. It is essential the TAP is reset before
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//! first being used.
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//! We cannot know for certain when the TAP state machine has been reset. 5
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//! consecutive TMS=1 transitions will take you there, but a reset of the
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//! target could undo this. It is the responsibility of the user of the TAP
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//! state machine.
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//! For convenience of users, this class provides a flag (resetDone::),
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//! with accessors by which reset state can be recorded.
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class TapStateMachine
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{
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public:
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  friend class  JtagSC;
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  friend class  TapAction;
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  friend class  TapActionDRScan;
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  friend class  TapActionIRScan;
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  friend class  TapActionReset;
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protected:
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  //! The number of cycles of TMS=1 required to force reset
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  static const int TAP_RESET_CYCLES = 5;
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  // Constructor
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  TapStateMachine();
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  // Accessor for TAP state
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  TapState  getState ();
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  // Accessors for TAP reset state
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  bool  getResetDone ();
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  void  setResetDone (bool  _resetState);
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  // Drive the TAP state machine
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  void  nextState (bool tms);
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  // Determine if we are in a particular target state
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  bool  targetState (TapState  target,
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                     bool     &tms);
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private:
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  //! The current TAP state
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  TapState  state;
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  //! True if the TAP state machine has been through a reset.
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  //! The state can be sure to match that of the target. Responsibility of
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  //! user classes to set this.
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  bool  resetDone;
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};      // class TapStateMachine
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#endif  // TAP_STATE_MACHINE__H

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