Bit 4—Reserved: This bit cannot be modified and is always read as 1.
Bit 3: Reset or NMI Select (RST/NMI): Selects either an internal reset or the NMI function at
watchdog timer overflow.
Bit 3: RST/NMI
Description
0
1
NMI function enabled
Reset function enabled
(Initial value)
Bits 2–0—Clock Select (CKS2–CKS0): These bits select one of eight clock sources obtained by
dividing the system clock (ø).
The overflow interval is the time from when the watchdog timer counter begins counting from
H'00 until an overflow occurs. In interval timer mode, OVF interrupts are requested at this
interval.
Bit 2:
CKS2
Bit 1:
CKS1
Bit 0:
CKS0
Clock Source Overflow Interval (øP = 10 MHz)
0
0
1
0
1
0
1
0
1
0
1
0
1
øP/2
51.2 µs
819.2 µs
1.6 ms
(Initial value)
øP/32
øP/64
øP/128
øP/256
øP/512
øP/2048
øP/4096
3.3 ms
1
6.6 ms
13.1 ms
52.4 ms
104.9 ms
225