upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 411

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

(2) Oscillation stabilization time select register (OSTS)
This register is used to select the X1 clock oscillation stabilization wait time when the STOP mode is released.
When the X1 clock is selected as the CPU clock, the operation waits for the time set using OSTS after the STOP
mode is released.
When the internal high-speed oscillation clock is selected as the CPU clock, confirm with OSTC that the desired
oscillation stabilization time has elapsed after the STOP mode is released. The oscillation stabilization time can
be checked up to the time set using OSTC.
OSTS can be set by an 8-bit memory manipulation instruction.
Reset signal generation sets OSTS to 05H.
Address: FFA4H
Symbol
OSTS
Remark f
Cautions 1. To set the STOP mode when the X1 clock is used as the CPU clock, set OSTS
Figure 14-2. Format of Oscillation Stabilization Time Select Register (OSTS)
OSTS2
7
0
0
0
0
1
1
After reset: 05H
Other than above
2. Do not change the value of the OSTS register during the X1 clock oscillation
3. The oscillation stabilization time counter counts up to the oscillation
4. The X1 clock oscillation stabilization wait time does not include the time until
X
: X1 clock oscillation frequency
before executing the STOP instruction.
stabilization time.
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.
Note, therefore, that only the status up to the oscillation stabilization time set by
OSTS is set to OSTC after STOP mode is released.
clock oscillation starts (“a” below).
OSTS1
6
0
0
1
1
0
0
• Desired OSTC oscillation stabilization time ≤ Oscillation stabilization time
X1 pin voltage
waveform
set by OSTS
CHAPTER 14 STANDBY FUNCTION
R/W
Preliminary User’s Manual U19014EJ1V0UD
OSTS0
5
0
1
0
1
0
1
STOP mode release
2
2
2
2
2
Setting prohibited
11
13
14
15
16
/f
/f
/f
/f
/f
X
X
X
X
X
4
0
a
Oscillation stabilization time selection
3
0
170.7
682.7
1.37 ms
2.73 ms
5.46 ms
f
X
µ
µ
= 12 MHz
OSTS2
s
s
2
OSTS1
128
512
1.024 ms
2.048 ms
4.096 ms
1
f
µ
µ
X
s
s
= 16 MHz
OSTS0
0
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