R8C datasheet(174/199 Pages) RENESAS

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R8C/10 Group

19. Usage Notes

Rev.1.20 Jan 27, 2006

page 164 of 180

REJ09B0019-0120

Figure 19.1 Example of Procedure for Changing Interrupt Factor

Disable Interrupt(2, 3)

Change interrupt factor (including mode of

peripheral functions)

Enable interrupt(2, 3)

Interrupt factor change

Change completed

• IR bit: The interrupt control register bit of an interrupt whose

factor is changed

NOTES:

1. Execute the above setting 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) interrupt.

To prevent interrupt requests from being generated when

using peripheral function interrupts other than the INTi

interrupt factor. In this case, use the I flag when all

maskable interrupts can be disabled. When all maskable

interrupts cannot be disabled, use the ILVL0 to ILVL2 bits

of the interrupt whose factor is changed.

3. Refer to “19.2.6 Changing Interrupt Control Register” for the

instructions to be used and their usage notes.

Set IR bit to “0” (interrupt not requested) using

MOV instruction(3)

19.2.5 Changing Interrupt Factor

The IR bit in the interrupt control register may be set to “1” (interrupt requested) when the interrupt

factor is changed. When using an interrupt, set the IR bit to “0” (interrupt not request) after changing

the interrupt factor. In addition, the changes of interrupt factors include all elements that change the

interrupt factors assigned to individual software interrupt numbers, polarities, and timing. Therefore,

when a mode change of the peripheral functions involves interrupt factors, edge polarities, and timing,

set the IR bit to “0” (interrupt not requested) after the change. Refer to each peripheral function for the

interrupts caused by the peripheral functions.

Figure 19.1 shows an Example of Procedure for Changing Interrupt Factor.

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