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(1) Watch timer
By using the main system clock or subsystem clock, interrupt requests (INTWTN0) are generated at preset
intervals.
An interrupt request (INTWTN0) occurs at an interval of 0.5 second when using the 32.768 kHz subsystem clock.
Also, an interrupt request (INTWTN0) can be generated at an interval of 1.0 seconds when using the 32.768 kHz
subsystem clock via a setting in the watch timer interrupt time select register (WTIM).
Interrupt Request Time
4
2
/f
W
5
2
/f
W
13
2
/f
W
14
2
/f
W
Remark f
: Watch timer clock frequency (f
W
f
: Main system clock oscillation frequency
X
f
: Subsystem clock oscillation frequency
XT
(2) Interval timer
By using the main system clock or subsystem clock, interrupt requests (INTWTNI0) are generated at preset
intervals.
Interval Time
4
2
/f
W
5
2
/f
W
6
2
/f
W
7
2
/f
W
8
2
/f
W
9
2
/f
W
10
2
/f
W
11
2
/f
W
Remark f
: Watch timer clock frequency (f
W
f
: Main system clock oscillation frequency
X
f
: Subsystem clock oscillation frequency
XT
CHAPTER 9 WATCH TIMER
Table 9-1. Watch Timer Interrupt Request Time
When Operated at f
=
X
10 MHz
409.6 µ s
819.2 µ s
0.2 s
0.41 s
8
/2
, f
X
XT
Table 9-2. Interval Timer Interval Time
When Operated at f
=
X
10 MHz
409.6 µ s
819.2 µ s
1.64 ms
3.28 ms
6.56 ms
13.1 ms
26.2 ms
52.4 ms
8
/2
, f
X
XT
User's Manual U15798EJ2V0UD
When Operated at f
=
XT
32.768 kHz
488 µ s
977 µ s
977 µ s
1.95 ms
0.25 s
0.5 s
0.5 s
1.0 s
, or f
/2)
XT
When Operated at f
=
XT
32.768 kHz
488 µ s
977 µ s
977 µ s
1.95 ms
1.95 ms
3.91 ms
3.91 ms
7.81 ms
7.81 ms
15.6 ms
15.6 ms
31.2 ms
31.2 ms
62.4 ms
62.4 ms
125 ms
, or f
/2)
XT
When Operated at f
/2 =
XT
16.384 kHz
When Operated at f
/2 =
XT
16.384 kHz
205
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