User`s guide

Schedulers and Timing
• Generated code that incorporates DSP /B IO S real-time operating sy stem
(RTOS)
• Generated code that does not include DSP/BIOS RTOS
Note In timer-based models, the timer counts through one full
base-sample-time before it creates an interrupt. When Simulink software
finally execute the model, it is for time 0.
The following figure shows the relationship between model startup and
execution. Execution starts where your model executes the first interrupt,
offset to the right of t=0 from the beginning of the time line. Before the first
interrupt, the simulation goes through the timer set up period and one base
rate period.
t=0.0
Base rate task
execution time
Timer setup
period
Base rate
period
Base rate
period
Base rate
period
Timer-based scheduling does not provide enough fl exibility for some systems.
Systems for control and communications m ust respond to asynchronous
events in real time. Such systems may need to handle a variety of hardware
interruptsinanasynchronous,oraperiodic ,fashion.
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