CHAPTER 9 WATCH TIMER
Preliminary User’s Manual U16315EJ1V0UD
203
(1) Watch timer
When the X1 input clock or subsystem clock is used, interrupt requests (INTWT) are generated at preset
intervals.
Table 9-1. Watch Timer Interrupt Time
Interrupt Time
When Operated at f
XT
= 32.768 kHz
When Operated at f
X
= 10 MHz
2
4
/f
W
488
µ
s
205
µ
s
2
5
/f
W
977
µ
s
410
µ
s
2
13
/f
W
0.25 s
0.105 s
2
14
/f
W
0.5 s
0.210 s
Remark
f
X
: X1 input clock oscillation frequency
f
XT
: Subsystem clock oscillation frequency
f
W
: Watch timer clock frequency
(2) Interval timer
Interrupt requests (INTWTI) are generated at preset time intervals.
Table 9-2. Interval Timer Interval Time
Interval Time
When Operated at f
XT
= 32.768 kHz
When Operated at f
X
= 10 MHz
2
4
/f
W
488
µ
s
205
µ
s
2
5
/f
W
977
µ
s
410
µ
s
2
6
/f
W
1.95 ms
820
µ
s
2
7
/f
W
3.91 ms
1.64 ms
2
8
/f
W
7.81 ms
3.28 ms
2
9
/f
W
15.6 ms
6.55 ms
2
10
/f
W
31.2 ms
13.1 ms
2
11
/f
W
62.4 ms
26.2 ms
Remark
f
X
: X1 input clock oscillation frequency
f
XT
: Subsystem clock oscillation frequency
f
W
: Watch timer clock frequency