CHAPTER 14 STANDBY FUNCTION
Preliminary User’s Manual U19014EJ1V0UD
410
(1) Oscillation stabilization time counter status register (OSTC)
This is the register that indicates the count status of the X1 clock oscillation stabilization time counter. When X1
clock oscillation starts with the internal high-speed oscillation clock used as the CPU clock, the X1 clock
oscillation stabilization time can be checked.
OSTC can be read by a 1-bit or 8-bit memory manipulation instruction.
When reset is released (reset by RESET input, POC, LVI, and WDT), the STOP instruction and MSTOP (bit 7 of
MOC register) = 1 clear OSTC to 00H.
Figure 14-1. Format of Oscillation Stabilization Time Counter Status Register (OSTC)
Address: FFA3H After reset: 00H R
Symbol
7 6 5 4 3 2 1 0
OSTC 0
0
0
MOST11
MOST13 MOST14 MOST15 MOST16
MOST11
MOST13
MOST14
MOST15
MOST16
Oscillation stabilization time status
f
X
= 12 MHz f
X
= 16 MHz
1 0 0 0 0
2
11
/f
X
min.
170.7
µ
s min. 128
µ
s min.
1 1 0 0 0
2
13
/f
X
min.
682.7
µ
s min. 512
µ
s min.
1 1 1 0 0
2
14
/f
X
min.
1.37 ms min. 1.024 ms min.
1 1 1 1 0
2
15
/f
X
min.
2.73 ms min. 2.048 ms min.
1 1 1 1 1
2
16
/f
X
min.
5.46 ms min. 4.096 ms min.
Cautions 1. After the above time has elapsed, the bits are set to 1 in order from MOST11 and
remain 1.
2. The oscillation stabilization time counter counts up to the oscillation
stabilization time set by OSTS. If the STOP mode is entered and then released
while the internal high-speed oscillation clock is being used as the CPU clock,
set the oscillation stabilization time as follows.
•
Desired OSTC oscillation stabilization time
≤
Oscillation stabilization time
set by OSTS
Note, therefore, that only the status up to the oscillation stabilization time set by
OSTS is set to OSTC after STOP mode is released.
3. The X1 clock oscillation stabilization wait time does not include the time until
clock oscillation starts (“a” below).
STOP mode release
X1 pin voltage
waveform
a
Remark
f
X
: X1 clock oscillation frequency
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