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Interrupt Tasks Section 4-3
Note 1. When the response notification method is set for interrupt notification (fixed
number), the Board requests execution of the interrupt task with the preset
task number.
2. When the response notification method is set for interrupt notification (re-
ception case number), the external interrupt task number is calculated with
the specified formula and the Board requests execution of the interrupt
task with that task number.
3. If an external interrupt task (0 to 255) has the same number as a power
OFF task (task 1), scheduled interrupt task (task 2 or 3), or I/O interrupt
task (100 to 131), the interrupt task will be executed for either interrupt con-
dition (external interrupt or the other interrupt condition). As a rule, task
numbers should not be duplicated.
4-3-2 Interrupt Task Priority
Execution of another interrupt task will be ended to allow the power OFF inter-
rupt task to execute. The CPU will reset but the terminated interrupt task will
not be executed following execution of the power OFF interrupt task.
Interrupt during Interrupt Task Execution
If an interrupt occurs while another interrupt task is being executed, the task
for the interrupt will not be executed until the original interrupt finishes execut-
ing.
CPU Unit
Cyclic task
Interrupt task
I/O memory
Specifies exter-
nal interrupt task
number and re-
quests interrupt
processing.
Serial Communications Board
Data
Cyclic task
Interrupt task A
Interrupt during
execution
Interrupt task B
Interrupt task A will continue
until it finishes executing.
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