(1) Watch timer
When the peripheral hardware clock or subsystem clock is used, interrupt request signals (INTWT) are
generated at preset intervals.
Interrupt Time
When Operated at
f
= 32.768 kHz
SUB
µ
4
2
/f
488
s
W
µ
5
2
/f
977
s
W
13
2
/f
0.25 s
W
14
2
/f
0.5 s
W
Remark
f
: Peripheral hardware clock frequency
PRS
f
: Subsystem clock frequency
SUB
f
:
Watch timer clock frequency (f
W
(2) Interval timer
Interrupt request signals (INTWTI) are generated at preset time intervals.
Interval Time
When Operated at
f
= 32.768 kHz
SUB
µ
4
2
/f
488
s
W
µ
5
2
/f
977
s
W
6
2
/f
1.95 ms
W
7
2
/f
3.91 ms
W
8
2
/f
7.81 ms
W
9
2
/f
15.6 ms
W
10
2
/f
31.3 ms
W
11
2
/f
62.5 ms
W
Remark
f
: Peripheral hardware clock frequency
PRS
f
: Subsystem clock frequency
SUB
f
:
Watch timer clock frequency (f
W
10.2 Configuration of Watch Timer
The watch timer includes the following hardware.
Counter
Prescaler
Control register
288
CHAPTER 10 WATCH TIMER
Table 10-1. Watch Timer Interrupt Time
When Operated at
f
= 2 MHz
PRS
1.02 ms
2.05 ms
0.52 s
1.05 s
7
/2
or f
PRS
Table 10-2. Interval Timer Interval Time
When Operated at
f
= 2 MHz
PRS
1.02 ms
2.05 ms
4.10 ms
8.20 ms
16.4 ms
32.8 ms
65.5 ms
131.1 ms
7
/2
or f
PRS
Table 10-3. Watch Timer Configuration
Item
5 bits × 1
11 bits × 1
Watch timer operation mode register (WTM)
Preliminary User's Manual U17260EJ3V1UD
When Operated at
When Operated at
f
= 5 MHz
f
PRS
PRS
µ
410
s
205
µ
819
s
410
0.210 s
0.105 s
0.419 s
0.210 s
)
SUB
When Operated at
When Operated at
f
= 5 MHz
f
PRS
PRS
µ
410
s
205
µ
820
s
410
1.64 ms
820
3.28 ms
1.64 ms
6.55 ms
3.28 ms
13.1 ms
6.55 ms
26.2 ms
13.1 ms
52.4 ms
26.2 ms
)
SUB
Configuration
When Operated at
= 10 MHz
f
= 20 MHz
PRS
µ
µ
s
102
s
µ
µ
s
205
s
52.5 ms
0.105 s
When Operated at
= 10 MHz
f
= 20 MHz
PRS
µ
µ
s
102
s
µ
µ
s
205
s
µ
µ
s
410
s
µ
820
s
1.64 ms
3.28 ms
6.55 ms
13.1 ms