M32CSLASH8B datasheet(388/406 Pages) RENESAS

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M32C/8B Group

25. Usage Notes

Preliminary specification

Specifications in this manual are tentative and subject to change.

REJ09B0450-0050 Rev.0.50 Oct 31, 2008

Page 371 of 385

25.7.4

Changing Interrupt Control Register

To change the Interrupt Control Register while an interrupt request is disabled, use the following instructions.

Changing IR bit:

The IR bit may not be changed to 0 (interrupt not requested) by writing, depending on which instruction is used.

If this causes a problem, use MOV instruction to change the register. (Technical update: TN-M16C-85-0204)

Changing any bits other than IR bit:

If an interrupt request is generated while writing to the corresponding Interrupt Control Register with

instructions such as MOV, the IR bit may not become 1 (interrupt requested) and the interrupt is not

acknowledged. If this causes a problem, use the following instructions to write to the register:

AND, OR, BCLR, BSET

25.7.5

Changing RLVL Register

The DMAII bit in the RLVL register is undefined after reset. To use interrupt priority level 7 for an interrupt,

set it to 0 before setting the Interrupt Control Register.

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