Renesas H8S/2111B - Manual (Page 398)

Rev. 1.00, 05/04, page 364 of 544
14.4.8 KCLK Fall Interrupt Operation
In this device, clearing the KBFSEL bit to 0 in KBCRH enables the KBF bit in KBCRL to be used
as a flag for the interrupt generated by the fall of KCLK input.
Figure 14.13 shows the setting method and an example of operation.
Start
Set KBIOE
KBF = 1
(interrupt generated)
KBE = 0
(KBBR reception
disabled)
Interrupt handling
Clear KBF
KCLK pin
fall detected?
KBFSEL = 0
KBIE = 1
(KCLK falling edge
interrupts enabled)
Yes
No
KCLK
(pin state)
KBF bit
Interrupt
generated Interrupt
generated Cleared
by software
Note: * The KBF setting timing is the same as the timing of KBF setting and KCLK automatic I/O inhibit bit generation in
figure 14.11. When the KBF bit is used as the KCLK input fall interrupt flag, the automatic I/O inhibit function does
not operate.
Figure 14.13 Example of KCLK Input Fall Interrupt Operation