UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 744

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(1) Oscillation stabilization time counter status register (OSTC)
742
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 or subsystem 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.
Address: FFA3H
Symbol
OSTC
Cautions 1. After the above time has elapsed, the bits are set to 1 in order from MOST11 and
Remark
Figure 20-1. Format of Oscillation Stabilization Time Counter Status Register (OSTC)
MOST
11
0
1
1
1
1
1
2. The oscillation stabilization time counter counts up to the oscillation stabilization time
3. The X1 clock oscillation stabilization time does not include the time until clock
f
X
7
0
: X1 clock oscillation frequency
After reset: 00H
MOST
remain 1.
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.
oscillation starts (“a” below).
13
0
0
1
1
1
1
Desired OSTC oscillation stabilization time
OSTS
MOST
14
0
0
0
1
1
1
6
0
X1 pin voltage
waveform
MOST
15
CHAPTER 20 STANDBY FUNCTION
R
0
0
0
0
1
1
Preliminary User’s Manual U19748EJ1V0UD
MOST
5
0
STOP mode release
16
0
0
0
0
0
1
Less than
2
2
2
2
2
2
MOST11
11
11
13
14
15
16
/f
/f
/f
/f
/f
/f
X
X
X
X
X
X
4
a
min.
min.
min.
min.
min.
1.02 ms min. 409.6 s min. 204.8 s min. 102.4 s min.
4.10 ms min.
8.19 ms min. 3.27 ms min.
16.38 ms min. 6.55 ms min.
32.77 ms min. 13.11 ms min. 6.55 ms min. 3.27 ms min.
f
Less than
1.02 ms
X
MOST13
= 2 MHz
Oscillation stabilization time status
3
1.64 ms min.
f
Less than
409.6 s
X
Oscillation stabilization time set by
MOST14
= 5 MHz
2
f
Less than
204.8 s
819.2 s min. 409.6 s min.
1.64 ms min. 819.2 s min.
3.27 ms min. 1.64 ms min.
X
MOST15
= 10 MHz
1
f
Less than
102.4 s
X
MOST16
= 20 MHz
0