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CHAPTER 8 WATCH TIMER
197
8.3
Watch Timer Control Register
The watch timer mode control register (WTM) controls the watch timer.
• Watch timer mode control register (WTM)
This register enables or disables the count clock and operation of the watch timer, sets the interval time of the
prescaler, controls the operation of the 5-bit counter, and sets the set time of the watch flag.
WTM is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears WTM to 00H.
Figure 8-2. Format of Watch Timer Mode Control Register (WTM) (1/2)
After reset: 00H
R/W
Address: FFFFF360H
7
6
5
4
3
2
1
0
WTM
WTM7
WTM6
WTM5
WTM4
WTM3
0
WTM1
WTM0
WTM7
Selects Count Clock of Watch Timer
0
f
xx
/2
9
(Main clock)
1
f
xt
(Subclock)
WTM6
WTM5
WTM4
Selects Interval Time of Prescaler
0
0
0
2
4
/f
W
(488
µ
s)
0
0
1
2
5
/f
W
(977
µ
s)
0
1
0
2
6
/f
W
(1.95 ms)
0
1
1
2
7
/f
W
(3.91 ms)
1
0
0
2
8
/f
W
(7.81 ms)
1
0
1
2
9
/f
W
(15.6 ms)
Others
Setting prohibited
WTM3
Selects Set Time of Watch Flag
0
2
14
/f
W
(0.5 s)
1
2
5
/f
W
(977
µ
s)
WTM1
Controls Operation of 5-bit Counter
0
Clears after operation stops.
1
Starts.
Summary of Contents for V850/SA1 mPD703015
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