Interrupt Masks; Interrupt Handling; Interrupt Variables - YASKAWA XTRAWARE - V3.0 Manual

4.11.4. Interrupt Masks

Using masks, you can specify which interrupt events need be handled, and
which need not be. This allows you to specify interrupt service routines for a
number of possible events, and then to deactivate them from within the
program as required.
If no mask is specified, the program will not react to any interrupt event. An
interrupt mask must therefore always be specified if interrupt are to be
used.
See section 4.11.6.2, Interrupt_mask.

4.11.5. Interrupt Handling

The process that occurs when an interrupt occurs is summarized below.
Detailed instructions on the use of the various variables and commands are
provided in the sections that follow.
♦ Event Occurs:
External event, such as a change in an input value
or
Internal event, such as a system variable meeting some condition.
♦ Interrupt is registered:
The relevant bit in the variable Interrupt_request is set to 1.
♦ If the registered interrupt is masked in Interrupt_mask, the program
flow is interrupted:
The XtraDrive stops retrieving commands from the user program
buffer.
♦ The XtraDrive executes the interrupt service routine for the highest
priority interrupt received.
♦ The XtraDrive clears the relevant bit in the variables Interrupt_request
and Interrupt_pending to indicate that the interrupt has been cleared.
♦ The XtraDrive executes the interrupt service routines for any other
outstanding interrupts, in order of priority.
♦ The XtraDrive continues running the program:
Either from the program line where it was initially interrupted
or
From another location specified in the interrupt service routine.

4.11.6. Interrupt Variables

The XtraDrive uses three variables (registers), each of which is a system
variable. Each variable consists of eight bits, one for each interrupt labeled
0 to 7.
XtraWare User Manual
Operating the XtraDrive Using XtraWare
77