INTERRUPTS
6.10 External interrupts
6.10.3 Switching of INT
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to interrupt request occurrence factor
When the INT interrupt request occurrence factor is switched in one of the following ways, there is a
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possibility that the corresponding interrupt request bit is set to “1”:
• Switching the factor from the level sense to the edge sense
• Switching the polarity
Therefore, after this switching, make sure to clear the corresponding interrupt request bit to “0.” Figure
6.10.6 shows an example of the switching procedure for the INT interrupt request’s occurrence factor.
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(1) Switching the factor from the level sense
to the edge sense
(2) Switching the polarity
Set the interrupt priority level to 0
Set the interrupt priority level to 0
or set the interrupt disable flag (I) to “1.”
or set the interrupt disable flag (I) to “1.”
(INTi interrupt is disabled.)
(INTi interrupt is disabled.)
Set the polarity select bit.
Clear the level sense/Edge sense select bit to “0.”
(Edge sense is selected.)
Clear the interrupt request bit to “0.”
Clear the interrupt request bit to “0.”
Set the interrupt priority level to one of
levels 1–7
or clear the interrupt disable flag (I) to “0.”
Set the interrupt priority level to one of
levels 1–7
(INTi interrupt request is acceptable.)
or clear the interrupt disable flag (I) to “0.”
(INTi interrupt request is acceptable.)
Note: The above settings must be done separately.
Multiple settings must not be done at the same time, in other words, they must not be
done only by 1 instruction.
Fig. 6.10.6 Example of switching procedure for INT interrupt request’s occurrence factor
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7906 Group User’s Manual Rev.2.0
6-22
RENESAS [ RENESAS TECHNOLOGY CORP ]
