NEC 78014Y Series, User Manual

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CHAPTER 10 WATCH TIMER
227
Symbol 7 6 5 4 3 2 1 0 Address When Reset R/W
TMC2 0 TMC26 TMC25 TMC24 TMC23 TMC22 TMC21 TMC20 FF4AH 00H R/W
TMC23 TMC20 Watch Flag Set Time Selection
0 0 2 14 /f
W
(0.5 s)
1 2 13 /f
W
(0.25 s)
0 1 2 5 /f
W
(977
µ
s)
1 2 4 /f
W
(488
µ
s)
TMC21 Prescaler Operation Control Note
0 Clear after operation stops
1 Operation enable
TMC22 5-Bit Counter Operation Control
0 Clear after operation stops
1 Operation enable
TMC26 TMC25 TMC24 Prescaler Interval Time
Selection
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)
Other than above Setting prohibited
Note Do not frequently clear the prescaler when using the watch timer.
Remarks 1. f
W
: Watch timer clock frequency (f
X
/2
8
or f
XT
)
2. Values in parentheses apply to operation with f
W
= 32.768 kHz.
(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.
TMC2 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets TMC2 to 00H.
Figure 10-3. Watch Timer Mode Control Register Format