2 register controlling standby function – NEC switch User Manual
Page 179
CHAPTER 12 STANDBY FUNCTION
User’s Manual U12978EJ3V0UD
179
12.1.2 Register controlling standby function
The wait time after the STOP mode is released upon interrupt request until oscillation stabilizes is controlled with
the oscillation stabilization time select register (OSTS).
OSTS is set with an 8-bit memory manipulation instruction.
RESET input sets OSTS to 04H. However, it takes 2
15
/f
X
until oscillation stabilizes after RESET input.
Figure 12-1. Format of Oscillation Stabilization Time Select Register
OSTS2
0
0
1
0
0
0
0
0
OSTS2 OSTS1 OSTS0
OSTS
R/W
FFFAH
04H
R/W
7
6
5
4
3
2
1
0
OSTS1
0
1
0
2
12
/f
X
2
15
/f
X
2
17
/f
X
(683 s)
(5.46 ms)
(21.8 ms)
OSTS0
0
0
0
Setting prohibited
Symbol
Address
After reset
Oscillation stabilization time selection
Other than above
µ
Caution
The wait time after the STOP mode is released does not include the time from STOP mode
release to clock oscillation start (“a” in the figure below), regardless of release by RESET input
or by interrupt generation.
STOP mode release
X1 pin voltage
waveform
a
Remarks 1. f
X
: System clock oscillation frequency
2. The parenthesized values apply to operation at f
X
= 6.0 MHz.