upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 343

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

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(2) Oscillation stabilization time select register (OSTS)
This register is used to select the high-speed system clock oscillation stabilization wait time when STOP mode is
released. The wait time set by OSTS is valid only after STOP mode is released when the high-speed system
clock is selected as the CPU clock. After STOP mode is released when the internal oscillation clock is selected,
check the oscillation stabilization time using OSTC.
OSTS can be set by an 8-bit memory manipulation instruction.
RESET input sets OSTS to 05H.
Cautions 1. To set the STOP mode when the high-speed system clock is used as the CPU clock, set
Address: FFA4H
Symbol
OSTS
2. Before setting OSTS, confirm with OSTC that the desired oscillation stabilization time has
3. If the STOP mode is entered and then released while the internal oscillation clock is being
4. The wait time when STOP mode is released does not include the time after STOP mode
Remark f
Figure 18-2. Format of Oscillation Stabilization Time Select Register (OSTS)
OSTS before executing a STOP instruction.
elapsed.
used as the CPU clock, set the oscillation stabilization time as follows.
The oscillation stabilization time counter counts only during the oscillation stabilization
time set by OSTS. Therefore, note that only the statuses during the oscillation stabilization
time set by OSTS are set to OSTC after STOP mode has been released.
release until clock oscillation starts (“a” below) regardless of whether STOP mode is
released by RESET input or interrupt generation.
OSTS2
• Desired OSTC oscillation stabilization time ≤ Oscillation stabilization time set by OSTS
7
0
0
0
0
1
1
After reset: 05H
Other than above
XP
: High-speed system clock oscillation frequency
OSTS1
6
0
0
1
1
0
0
X1 pin voltage
waveform
CHAPTER 18 STANDBY FUNCTION
R/W
OSTS0
User’s Manual U16962EJ3V0UD
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
XP
XP
XP
XP
XP
4
0
a
Oscillation stabilization time selection
3
0
204.8
819.2
1.64 ms
3.27 ms
6.55 ms
f
XP
µ
µ
OSTS2
= 10 MHz
s
s
2
OSTS1
128
512
1.02 ms
2.04 ms
4.09 ms
1
f
XP
µ
µ
s
s
= 16 MHz
OSTS0
0
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