Watch Timer Mode Control Register Format - NEC PD78076 User Manual

(2) Watch timer mode control register (TMC2)
This register sets the watch timer operating mode, watch flag set time and prescaler interval time and
enables/disables prescaler and 5-bit counter operations.
manipulation instruction.
RESET input sets TMC2 to 00H.
Figure 11-3. Watch Timer Mode Control Register Format
7 6 5
Symbol
TMC2 0 TMC26 TMC25 TMC24
TMC20 Watch Operating Mode Selection
0 Normal operating mode (flag set at f
1 Fast feed operating mode (flag set at f
TMC21 Prescaler Operation Control
0 Clear after operation stop
1 Operation enable
TMC22 5-Bit Counter Operation Control
0 Clear after operation stop
1 Operation enable
Watch Flag Set Time Selection
TMC23
f = 5.0 MHz Operation
XX
14
0 2 /f (0.4 sec)
W
13
1 2 /f (0.2 sec)
W
TMC26 TMC25 TMC24
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
Other than above
Caution When the watch timer is used, the prescaler should not be cleared frequently.
Remarks 1. f : Watch timer clock frequency (f
W
2. f : Main system clock frequency (f
XX
3. f : Main system clock oscillation frequency
X
4. f : Subsystem clock oscillation frequency
XT
CHAPTER 11 WATCH TIMER
4 3 2 1 0
TMC23 TMC22 TMC21 TMC20
14
/2 )
W
5
/2 )
W
f = 4.19 MHz Operation
XX
14
2 /f (0.5 sec)
W
13
2 /f (0.25 sec)
W
Prescaler Interval Time Selection
f = 5.0 MHz Operation
XX
4
µ
2 /f (410 s)
W
5
µ
2 /f (819 s)
W
6
2 /f (1.64 ms)
W
7
2 /f (3.28 ms)
W
8
2 /f (6.55 ms)
W
9
2 /f (13.1 ms)
W
Setting prohibited
TMC2 is set with a 1-bit or 8-bit memory
After
Address
Reset
FF4AH 00H
f = 32.768 kHz Operation
XT
14
2 /f
13
2 /f
f = 4.19 MHz Operation
XX
4
µ
2 /f (488 s)
W
5
µ
2 /f (977 s)
W
6
2 /f (1.95 ms)
W
7
2 /f (3.91 ms)
W
8
2 /f (7.81 ms)
W
9
2 /f (15.6 ms)
W
/2 7 or f )
XX XT
or f /2)
X X
R/W
R/W
(0.5 sec)
W
(0.25 sec)
W
f = 32.768 kHz Operation
XT
4
µ
2 /f (488 s)
W
5
µ
2 /f (977 s)
W
6
2 /f (1.95 ms)
W
7
2 /f (3.91 ms)
W
8
2 /f (7.81 ms)
W
9
2 /f (15.6 ms)
W
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