User`s guide

Configuring Simulink for DSP Systems
2-15
of servicing the loop in cases when inline code can be used with only a modest
increase in the file size.
However, because typical DSP processors offer zero-overhead looping, code
size is the primary optimization constraint in most designs. It is therefore
more efficient to minimize code size by generating a loop for every instance
of iteration, regardless of the number of repetitions. This is what the
'RTWOptions' loop-rolling setting in dspstartup accomplishes.
Miscellaneous Settings
The dspstartup M-file adjusts several other parameters to make it easier to
run DSP simulations. Two of the important settings are:
•
'StopTime' is set to 'inf', which allows the simulation to run until you
manually stop it by selecting
Stop from the Simulation menu, or by pressing
the
Stop Simulation button on the toolbar. To set a finite stop time, enter a
value for the
Stop time parameter in the Simulation Parameters dialog
box.
•
'Solver' is set to 'fixedstepdiscrete', which selects the fixed-step solver
option instead of Simulink’s default variable-step solver (this mode enables
code generation from the model using the Real-Time Workshop). See
“Discrete-Time Signals” on page 3-3 for more information about the various
solver settings.