Datasheet

Section 4 Interrupt Controller
REJ09B0465-0300 Rev. 3.00 Page 107 of 982
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
4.6.5 Changing PMR, ISCRH, ISCRL and INCCR
When the PMR, ISCRH, ISCRL, and INCCR are modified to change an IRQ7 to IRQ0 interrupt
function, the interrupt request flag bit may be set to 1 at an unintended time. To prevent this, the
pin function should be changed when the interrupt request is disabled, then the interrupt request
flag should be cleared to 0 after a specific interval time*.
Figure 4.7 shows the procedure to modify PMR (port mode register), ISCRH, ISCRL, and INCCR
and clear the interrupt request flags.
Note: Two states + a minimum interval for input (t
IH
/t
IL
)
Set I bit in CCR
to 1.
Clear I bit in CCR
to 0.
Wait for a specific
period.
Clear interrupt request
flag to 0.
Modify PMR, ISCRH,
ISCRL, and INCCR.
The interrupt is disabled.
(Interrupts can also be
disabled by setting IER.)
The Interrupt is enabled.
After setting each register,
the interrupt request flag
should be cleared to 0 after
waiting for a specific period.
Figure 4.7 Procedure to Modify PMR, ISCRH, ISCRL, and INCCR and Clear Interrupt
Request Flag
4.6.6 IRQ Status Register (ISR)
Depending on the pin state after a reset, IRQnF may be set to 1. Therefore, always read ISR and
clear it to 0 after resets.