User`s guide

Interrupt Handling
11-13
• VME Interrupt Offset Number(s) — the Real-Time Workshop uses this
number in the call to
intConnect(INUM_TO_IVEC(#),...). You should
specify a unique vector offset number for each interrupt number.
• Preemption Flag(s) — By default, higher priority interrupts can preempt
lower priority interrupts in VxWorks. If desired, you can lock out interrupts
during the execution of a ISR by setting the preemption flag to 0. This causes
intLock() and intUnlock() calls to be inserted at the beginning and end of
the ISR respectively. This should be used carefully since it increases the
systems interrupt response time for all interrupts at the
intLockLevelSet()
and below.
• IRQ Direction — In simulation mode, a scalar IRQ direction is applied to all
control inputs, and is specified as 1 (rising), -1 (falling), or 0 (either).
Configuring inputs separately in simulation is done prior to the control
input. For example, a Gain block set to -1 prior to a specific IRQ input will
change the behavior of one control input relative to another. In RTW mode
the IRQ direction parameter is ignored.