CHAPTER 9 WATCH TIMER
Preliminary User’s Manual U16315EJ1V0UD
207
9.4.2 Interval timer operation
The watch timer operates as interval timer which generates interrupt requests (INTWTI) repeatedly at an interval of
the preset count value.
The interval time can be selected with bits 4 to 6 (WTM4 to WTM6) of the watch timer operation mode register
(WTM).
When bit 0 (WTM0) of the WTM is set to 1, the count operation starts. When this bit is set to 0, the count operation
stops.
Table 9-5. Interval Timer Interval Time
WTM6
WTM5
WTM4
Interval Time
When Operated at
f
XT
= 32.768 kHz (WTM7 = 1)
When Operated at
f
X
= 10 MHz (WTM7 = 0)
0
0
0
2
4
/f
W
488
µ
s
205
µ
s
0
0
1
2
5
/f
W
977
µ
s
410
µ
s
0
1
0
2
6
/f
W
1.95 ms
820
µ
s
0
1
1
2
7
/f
W
3.91 ms
1.64 ms
1
0
0
2
8
/f
W
7.81 ms
3.28 ms
1
0
1
2
9
/f
W
15.6 ms
6.55 ms
1
1
0
2
10
/f
W
31.2 ms
13.1 ms
1
1
1
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