R8C2K datasheet(138/471 Pages) RENESAS

138 / 471 page

R8C/2K Group, R8C/2L Group

12. Interrupts

Rev.1.10

Dec 21, 2007

Page 121 of 450

REJ09B0406-0110

12.6.4

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 12.22 shows an Example of Procedure for Changing Interrupt Sources.

Figure 12.22

Example of Procedure for Changing Interrupt Sources

NOTES:

1. Execute the above settings individually. Do not execute two

or more settings at once (by one instruction).

2. To prevent interrupt requests from being generated 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 12.6.5 Changing Interrupt Control Register

Contents for the instructions to be used and usage notes.

Interrupt source change

Disable interrupts(2, 3)

Set the IR bit to 0 (interrupt not requested)

using the MOV instruction(3)

Change interrupt source (including mode

of peripheral function)

Enable interrupts(2, 3)

Change completed

IR bit:

The interrupt control register bit of an

interrupt whose source is changed.

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