Omron CP1H CPU User Manual

187
Interrupt Functions Section 5-1
a. The following example shows duplicate processing by an interrupt
task, which interrupts processing of a +B instruction between the first
and third operands and overwrites the same memory address.
The interrupt occurs during processing of the +B instruction and the result is
saved temporarily without being written to the destination word (D0).
The interrupt task transfers the value of #0010 to D0, but the saved result of
the +B instruction (1235) is written to D0 when processing returns to the cyclic
task. In the end, the interrupt task’s processing has no effect.
Prevention of Duplicate Processing
+B
D0
#0001
D0
MOV
#0010
D0
D0
1234
0010
1235
Processing
interrupted.
Cyclic task
Interrupt task
Read D0 value (1234).
BCD addition: 1234 + 1 = 1235
Interrupt occurs.
MOV executed
0010 moved to D0.
Interrupt completed.
Data saved.
Addition result (1235)
Write addition result (1235).
Processing
of +B
instruction
Processing
continues.
Flow of Processing
+B
D0
#0001
D0
DI
EI
Cyclic task
Disables execution of
interrupt programs.
Enables execution of
interrupt programs.

Omron CP1H CPU Specifications

General

Brand	Omron
Model	CP1H CPU
Category	Computer Hardware
Language	English