MB95630H Series
MN702-00009-2v0-E FUJITSU SEMICONDUCTOR LIMITED 115
CHAPTER 9 WATCH PRESCALER
9.3 Interrupt
9.3 Interrupt
An interrupt request is generated when the selected interval time of the watch
prescaler has elapsed (interval timer function).
â– Interrupts in Operation of Interval Timer Function (Watch Prescaler
Interrupts)
In any mode except the stop mode in which the subclock mode or the sub-CR clock mode is
used, if the watch prescaler counter counts down using the subclock divided by two or the sub-
CR clock divided by two and the selected interval time elapses, the watch prescaler interrupt
request flag bit is set to "1" (WPCR:WTIF = 1). At that time, if the watch prescaler interrupt
request enable bit has been enabled (WPCR:WTIE = 1), an interrupt request is output from the
watch prescaler to the interrupt controller.
• Regardless of the value in the WTIE bit, the WTIF bit is set to "1" as soon as the time set
by the watch prescaler interrupt interval time select bits has elapsed.
• When the WTIF bit is set to "1", changing the WTIE bit from the disable state to the enable
state (WPCR:WTIE = 0 → 1) immediately generates an interrupt request.
• The WTIF bit will not be set to "1" if the counter is cleared (WPCR:WCLR = 1) at the
same time as the selected bit overflows.
• Write "0" to the WTIF bit in the interrupt service routine to clear an interrupt request.
Note:
To enable the output of interrupt requests after releasing a reset, set the WTIE bit in the
WPCR register to "1" and clear the WTIF bit in the same register simultaneously.
Table 9.3-1 Interrupt of Watch Prescaler
Item Description
Interrupt condition Interval time set by "WPCR:WTC[2:0]" has elapsed.
Interrupt flag WPCR:WTIF
Interrupt enable WPCR:WTIE
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