M306H7MG-XXXFP Datasheet, PDF (311/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
19. USAGE NOTES
Changing the interrupt source
Disable interrupts (Note 2, Note 3)
Change the interrupt generate factor (including a mode change of peripheral function)
Use the MOV instruction to clear the IR bit to “0” (interrupt not requested) (Note 3)
Enable interrupts (Note 2, Note 3)
End of change
IR bit: A bit in the interrupt control register for the interrupt whose interrupt generate factor is to
be changed
Note 1: The above settings must be executed individually. Do not execute two or more settings
simultaneously (using one instruction).
Note 2: Use the I flag for the INTi interrupt (i = 0 to 5).
For the interrupts from peripheral functions other than the INTi interrupt, turn off the
peripheral function that is the source of the interrupt in order not to generate an interrupt
request before changing the interrupt generate factor. In this case, if the maskable interrupts
can all be disabled without causing a problem, use the I flag. Otherwise, use the corresponding
ILVL2 to ILVL0 bit for the interrupt whose interrupt generate factor is to be changed.
Note 3: Refer to Section “Rewrite the Interrupt Control Register” for details about the
instructions to use and the notes to be taken for instruction execution.
Figure 19.1 Procedure for Changing the Interrupt Generate Factor
19.3.5 INT Interrupt
(1) Either an “L” level of at least tW(INL) or an “H” level of at least tW(INH) width is necessary for the
signal input to pins INT0 through INT5 regardless of the CPU operation clock.
(2) If the POL bit in the INT0IC to INT5IC registers or the IFSR7 to IFSR0 bits in the IFSR register are
changed, the IR bit may inadvertently set to 1 (interrupt requested). Be sure to clear the IR bit to 0
(interrupt not requested) after changing any of those register bits.
19.3.6 Rewrite the Interrupt Control Register
(1) The interrupt control register for any interrupt should be modified in places where no requests for that
interrupt may occur. Otherwise, disable the interrupt before rewriting the interrupt control register.
(2) To rewrite the interrupt control register for any interrupt after disabling that interrupt, be careful with
the instruction to be used.
• Changing any bit other than the IR bit
If while executing an instruction, a request for an interrupt controlled by the register being modified occurs,
the IR bit in the register may not be set to “1” (interrupt requested), with the result that the interrupt request
is ignored. If such a situation presents a problem, use the instructions shown below to modify the register.
Usable instructions: AND, OR, BCLR, BSET
Rev.2.10 Oct 25, 2006 Page 311 of 326
REJ03B0152-0210