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Start the Simulink Debugger

You can start the debugger from either a Simulink® model window or from the MATLAB® Command Window.

Starting from a Model Window

  1. In a model window, on the Debug tab, select Breakpoints List > Debug Model.

    The debugger graphical user interface opens. See Debugger Graphical User Interface.

  2. Continue selecting toolbar buttons.


When running the debugger in graphical user interface (GUI) mode, you must explicitly start the simulation. For more information, see Start a Simulation.


When starting the debugger from the GUI, you cannot enter debugger commands in the MATLAB command window. For this, you must start the debugger from the command window using the sim or sldebug commands.

Starting from the Command Window

  1. In the MATLAB Command Window, enter either

    • the sim command. For example, enter

      sim('vdp', 'StopTime', '10', 'debug', 'on')

    • or the sldebug command. For example, enter

      sldebug 'vdp'

    In both cases, the example model vdp loads into memory, starts the simulation, and stops the simulation at the first block in the model execution list.

  2. The debugger opens and a debugger command prompt appears within the MATLAB command window. Continue entering debugger commands at this debugger prompt.

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