Changing Interrupt Sources - Renesas R8C/18 Series Hardware Manual

R8C/18 Group, R8C/19 Group
12.5.5

Changing Interrupt Sources

The IR bit in the interrupt control register may be set to 1 (interrupt requested) when the interrupt
source changes. When using an interrupt, set the IR bit to 0 (no interrupt requested) after changing
the interrupt source.
In addition, changes of interrupt sources include all factors that change the interrupt sources
assigned to individual software interrupt numbers, polarities, and timing. Therefore, if a mode change
of a peripheral function involves interrupt sources, edge polarities, and timing, set the IR bit to 0 (no
interrupt requested) after the change. Refer to the individual peripheral function for its related
interrupts.
Figure 12.20 shows an Example of Procedure for Changing Interrupt Sources.
Figure 12.20 Example of Procedure for Changing Interrupt Sources
Rev.1.30 Apr 14, 2006
REJ09B0222-0130
Interrupt source change
Disable interrupts
Change interrupt source (including mode
of peripheral function)
Set the IR bit to 0 (interrupt not requested) using
the MOV instruction
Enable interrupts
Change completed
IR bit: The interrupt control register bit of an
interrupt whose source is changed.
NOTES:
1. Execute the above settings individually. Do not execute
two or more settings at once (by one instruction).
2. Use the I flag for the INTi (i = 0 to 3) interrupts.
To prevent interrupt requests from being generated when
using peripheral function interrupts other than the INTi
interrupt, disable the peripheral function before changing
the interrupt source. In this case, use the I flag if all
maskable interrupts can be disabled. If all maskable
interrupts cannot be disabled, use bits ILVL0 to ILVL2 of
the interrupt whose source is changed.
3. Refer to 12.5.6 Changing Interrupt Control Register
Contents for the instructions to be used and usage notes.
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12. Interrupts