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Table 11.3-1 Functions of bits in watch timer control register (WTC)
Bit name
WDCS:
bit7
Watchdog timer clock
source selection bit
SCE:
Bit indicating end of
bit6
oscillation stabilization
wait time for sub-clock
WTIE:
bit5
Watch timer interval
interrupt permit bit
WTOF:
bit4
Watch timer interrupt
request flag bit
WTR:
bit3
Watch counter clear
bit
bit2
WTC2, WTC1, WTC0:
to
Watch timer interval
bit0
selection bits
This bit is for selecting the clock source for the watchdog timer.
•
If set to "0", this bit specifies clock for the watch timer; if set to "1", it
specifies clock for the timebase timer. If the mode transits to the sub-
clock mode with setting to "1", the watchdog timer stops.
•
This bit is initialized to "1" by a reset.
This bit indicates that the oscillation stabilization wait time of the sub-clock
has ended.
•
If set to "0", this bit indicates that the oscillation stabilization wait time
of the sub-clock is ongoing.
•
The oscillation stabilization wait time of the sub-clock is fixed at 2
cycles of the sub-clock.
•
This bit is initialized to "0" by a power-on reset or stoppage.
This bit is for permitting interval interrupts by the watch timer.
•
If set to "1", this bit permits interrupts; if set to "0", it prohibits
interrupts.
•
This bit is initialized to "0" by a reset
This bit indicates that an interrupt request by the watch timer has been
issued.
•
If this bit is set to "1" and the WTIE bit is set to "1", an interrupt request
has been issued.
•
This bit is set to "1" at each interval time specified by the WTC2 to
WTC0 bits.
•
This bit is cleared to "0" by writing "0", a transition to the stop mode,
and a reset.
•
Writing "1" to this bit has no effect.
This bit is for clearing all bits to 0 in the watch timer counter.
•
Writing "0" to this bit clears the watch timer counter to "0".
•
Writing "1" to this bit has no effect.
•
During reading, "1" is always read and output.
These bits specify the interval of the watch timer.
•
These bits are initialized to "000
•
When changing the bit settings, clear the WTOF bit at the same time.
CHAPTER 11 WATCH TIMER
Function
" by a reset.
B
14
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