M16C62P_06 Datasheet, PDF (382/421 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

M16C/62P Group (M16C/62P, M16C/62PT)
24. Precautions
24.7.4 Changing the Interrupt Generate Factor
If the interrupt generate factor is changed, the IR bit in the interrupt control register for the changed interrupt
may inadvertently be set to “1” (interrupt requested). If you changed the interrupt generate factor for an
interrupt that needs to be used, be sure to clear the IR bit for that interrupt to “0” (interrupt not requested).
Changing the interrupt generate factor refered to here means any act of changing the source, polarity or timing
of the interrupt assigned to each software interrupt number. Therefore, if a mode change of any peripheral
function involves changing the generate factor, polarity or timing of an interrupt, be sure to clear the IR bit for
that interrupt to “0” (interrupt not requested) after making such changes. Refer to the description of each
peripheral function for details about the interrupts from peripheral functions.
Figure 24.3 shows the Procedure for Changing the Interrupt Generate Factor.
Changing the interrupt source
Disable interrupts ^{(2, 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) ⁽³⁾
Enable interrupts ^{(2, 3)}
End of change
IR bit: A bit in the interrupt control register for the interrupt whose interrupt generate factor is
to be changed
NOTES :
1. The above settings must be executed individually. Do not execute two or more settings
simultaneously (using one instruction).
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.
3. Refer to 18.4.6 Rewrite the Interrupt Control Register for details about the
instructions to use and the notes to be taken for instruction execution.
Figure 24.3 Procedure for Changing the Interrupt Generate Factor
24.7.5 INT Interrupt
• Either an “L” level of at least tW(INH) or an “H” level of at least tW(INL) width is necessary for the signal
input to pins INT0 through INT5 regardless of the CPU operation clock.
• 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.
Rev.2.41 Jan 10, 2006 Page 367 of 390
REJ09B0185-0241