NEC 78K0/KD1 Series User Manual page 203

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