Mitsubishi 00JCPU User Manual page 55

(3) Operation when an interrupt factor occurs
There are restrictions on interrupt programs depending on the interrupt factor occurrence timing.
(a) When an interrupt factor occurs before the interrupt program execution status is
enabled
The CPU module stores the interrupt factor occurred.
As soon as the interrupt program execution status is enabled, the CPU module executes the interrupt program
corresponding to the stored interrupt factor.
Main routine
program
Interrupt
program
Figure 2.11 When an interrupt factor occurs before interrupts are enabled
When the same interrupt factor occurs more than one time before the interrupt program execution status is
enabled, the CPU module operates as follows:
1) Basic model QCPU
The CPU module stores the interrupt factors of I0 to I15, I28 to I31, and I50 to I127 only once.
2) High Performance model QCPU, Process CPU, or Redundant CPU
The CPU module stores the interrupt factors of I0 to I27, I28 to I31, I50 to I255, and fixed scan execution type
programs only once.
As for I32 to I41 and I49, the CPU module discards the interrupt factors occurred while interrupts are
disabled.
(b) When an interrupt factor occurs in the STOP or PAUSE status
The CPU module executes the interrupt program as soon as the interrupt program execution status is enabled
after the CPU module status is changed to RUN.
Main routine
program
Interrupt
program
Figure 2.12 When an interrupt factor occurs in the STOP or PAUSE status
Interrupt factor
occurrence
Not executed because
the interrupt program
execution status is
disabled (DI).
STOP/PAUSE
Interrupt factor
occurrence
Not executed because
the CPU module is in
the STOP status.
CHAPTER2 SEQUENCE PROGRAMS
Interrupt
enabled (EI)
Execution
Executed as soon as
the interrupt program
execution status
changes to enabled.
RUN
Interrupt
enabled (EI)
Execution
Executed as soon as the interrupt
program execution status changes
to enabled after the CPU module
status is changed from
STOP/PAUSE to RUN.
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