Interrupts Of Watch Prescaler - Fujitsu F2MC-8FX Hardware Manual

CHAPTER 13 WATCH PRESCALER
13.4

Interrupts of Watch Prescaler

An interrupt request is generated when the selected interval time of the watch prescaler
has elapsed (interval timer function).
Interrupts in Operation of Interval Timer Function (Watch Interrupts)
In any mode other than the main stop mode, the watch interrupt request flag bit is set to "1" (WPCR:WTIF
= 1), when the watch prescaler counter counts up by using the source oscillation of the subclock and the
time of the interval timer has elapsed. If the interrupt request enable bit is also enabled (WPCR:WTIE = 1)
and watch counter start interrupt request enable bit of the watch counter is disabled (WCSR: ISEL0), an
interrupt request (IRQ20) occurs from watch prescaler to an interrupt controller.
• Regardless of the value in the WTIE bit, the WTIF bit is set to "1" when the time set by the watch
interrupt interval time select bits has been reached.
• 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 cannot be set when 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 processing routine to clear an interrupt request to "0".
Note:
When enabling the output of interrupt requests (WPCR:WTIE = 1) after canceling a reset, always
clear the WTIF bit at the same time (WPCR:WTIF = 0).
Interrupts of Watch Prescaler
Table 13.4-1 Interrupts of Watch Prescaler
Interrupt condition
Interrupt flag
Interrupt enable
Register and Vector Table Related to Interrupts of Watch Prescaler
Table 13.4-2 Register and Vector Table Related to Interrupts of Watch Prescaler
Interrupt
source
Watch
prescaler*
*: The watch prescaler shares the same interrupt request number and vector table as the watch counter.
CHAPTER 8 INTERRUPTS describes the interrupt request numbers and vector tables for all peripheral
functions.
198
Item
Interval time set by "WPCR:WTC1" and "WTC0" has elapsed.
WPCR:WTIF
WPCR:WTIE
Interrupt level setup register
Interrupt
request No.
IRQ20
Description
Register Setting bit
ILR5 L20
Vector table address
Upper Lower
FFD2 FFD3
H H