Watch Timer Control Register - NEC Renesas V850/SC1 User Manual

9.3 Watch Timer Control Register

The watch timer mode control register (WTNM), watch timer high-speed clock select register (WTNHC), and watch
timer clock select register (WTNCS) control the watch timer. The watch timer should be operated after setting the
count clock and interval time.
(1) Watch timer mode control register (WTNM)
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 interrupt time of the watch timer.
WTNM is set by an 8-bit or 1-bit memory manipulation instruction.
RESET input clears WTNM to 00H.
After reset: 00H
7
WTNM WTNM7
WTNM6
0
0
0
0
1
1
1
1
WTNM3
0
0
1
1
WTM1
0
1
WTNM0
0
1
Remarks 1. f
CHAPTER 9 WATCH TIMER FUNCTION
R/W Address: FFFFF360H
6 5
WTNM6 WTNM5 WTNM4
WTNM5 WTNM4
4
0 0 2 /f
5
0 1 2 /f
6
1 0 2 /f
7
1 1 2 /f
8
0 0 2 /f
9
0 1 2 /f
10
1 0 2 /f
11
1 1 2 /f
WTNM2
14
0 2 /f (0.5 s)
W
13
1 2 /f (0.25 s)
W
(977 µ s)
5
0 2 /f
W
(488 µ s)
4
1 2 /f
W
Controls operation of 5-bit counter
Clears after operation stops
Starts
Enables operation of watch timer
Stops operation (clears both prescaler and 5-bit counter)
Enables operation
: Watch timer clock frequency
W
2. Values in parentheses apply when f
3. For the settings of WTNM7, refer to 9.3 (3) Watch timer clock select register
(WTNCS).
User's Manual U15109EJ3V0UD
4 3 2
WTNM3 WTNM2
Selects interval time of prescaler
(488 µ s)
W
(977 µ s)
W
(1.95 ms)
W
(3.91 ms)
W
(7.81 ms)
W
(15.6 ms)
W
(31.2 ms)
W
(62.4 ms)
W
Selects interrupt time of watch timer
= 32.768 kHz.
W
<1> <0>
WTNM1 WTNM0
311