UPD78F0138 NEC, UPD78F0138 Datasheet - Page 124

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

(5) Oscillation stabilization time counter status register (OSTC)
124
This is the status register of the X1 input clock oscillation stabilization time counter. If the Ring-OSC clock is used
as the CPU clock, the X1 input 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, clock monitor, and WDT), the STOP instruction,
MSTOP = 1, and MCC = 1 clear OSTC to 00H.
Address: FFA3H
Symbol
OSTC
Figure 5-6. Format of Oscillation Stabilization Time Counter Status Register (OSTC)
Remarks 1. Values in parentheses are reference values for operation with f
Cautions 1. After the above time has elapsed, the bits are set to 1 in order from MOST11 and
MOST11
7
0
1
1
1
1
1
After reset: 00H
2. f
2. If the STOP mode is entered and then released while the Ring-OSC is being used
3. The wait time when STOP mode is released does not include the time after STOP
XP
MOST13
remain 1.
as the CPU clock, set the oscillation stabilization time as follows.
The X1 oscillation stabilization time counter counts up to the 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.
mode release until clock oscillation starts (“a” below) regardless of whether
STOP mode is released by RESET input or interrupt generation.
: X1 input clock oscillation frequency
6
0
0
1
1
1
1
• Desired OSTC oscillation stabilization time ≤ Oscillation stabilization time
X1 pin voltage
waveform
set by OSTS
R
CHAPTER 5 CLOCK GENERATOR
MOST14
User’s Manual U16228EJ2V0UD
5
0
0
0
1
1
1
STOP mode release
MOST11
MOST15
4
0
0
0
1
1
a
MOST13
MOST16
3
0
0
0
0
1
2
2
2
2
2
MOST14
11
13
14
15
16
Oscillation stabilization time status
/f
/f
/f
/f
/f
XP
XP
XP
XP
XP
2
min. (204.8
min. (819.2
min. (1.64 ms min.)
min. (3.27 ms min.)
min. (6.55 ms min.)
MOST15
XP
µ
µ
1
s min.)
s min.)
= 10 MHz.
MOST16
0