UPD78F9418AGK-9EU Renesas Electronics America, UPD78F9418AGK-9EU Datasheet - Page 133

• Manufacturer Part Number: UPD78F9418AGK-9EU
• Manufacturer: Renesas Electronics America

Specifications of UPD78F9418AGK-9EU

• Lead Free Status / Rohs Status: Supplier Unconfirmed

8.3 Register Controlling Watch Timer
Symbol
WTM
The watch timer mode control register (WTM) is used to control the watch timer.
• Watch timer mode control register (WTM)
Remarks 1. f
WTM selects a count clock for the watch timer and specifies whether to enable operation of the timer. It also
specifies the prescaler interval and how the 5-bit counter is controlled.
WTM is set using a 1-bit or 8-bit memory manipulation instruction.
RESET input sets WTM to 00H.
WTM7 WTM6 WTM5 WTM4
WTM7
WTM6
WTM1
WTM0
Other than above
7
0
0
0
0
1
1
0
1
0
1
0
1
WTM5
2. f
3. f
4. The parenthesized values apply to operation at f
Cleared after stop
Started
Operation stopped (both prescaler and timer cleared)
Operation enabled
f
f
X
XT
6
0
0
1
1
0
0
/2
(32.768 kHz)
W
X
XT
7
:
(39.1 kHz)
: Watch timer clock frequency (f
WTM4
: Subsystem clock oscillation frequency
5
0
1
0
1
0
1
Main system clock oscillation frequency
2
2
2
2
2
2
Setting prohibited
Figure 8-2. Format of Watch Timer Mode Control Register
4
5
6
7
8
9
4
/f
/f
/f
/f
/f
/f
W
W
W
W
W
W
(488 s)
(977 s)
(1.95 ms)
(3.91 ms)
(7.81 ms)
(15.6 ms)
3
0
2
0
CHAPTER 8 WATCH TIMER
User’s Manual U13952EJ3V1UD
WTM1 WTM0
1
Watch timer count clock selection
Control of 5-bit counter operation
X
Prescaler interval selection
/2
0
Watch timer operation
7
or f
XT
)
Address
FF4AH
W
= 32.768 kHz.
After reset
00H
R/W
R/W
131