APPENDIX D LIST OF CAUTIONS
User’s Manual U16899EJ2V0UD
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(3/24)
Chapter
Cl
assi
fi
cati
on
Function Details
of
Function
Cautions Page
To set the STOP mode when the high-speed system clock is used as the CPU
clock, set OSTS before executing a STOP instruction.
p. 117
Before setting OSTS, confirm with OSTC that the desired oscillation stabilization
time has elapsed.
p. 117
Soft
If the STOP mode is entered and then released while the Ring-OSC 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
The 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.
p. 117
Main
clock
OSTS:
Oscillation
stabilization
time select
register
The wait time when STOP mode is released does not include the time after STOP
mode release until clock oscillation starts (“a” below) regardless of whether STOP
mode is released by RESET input or interrupt generation.
p. 117
High-
speed
system
clock
oscillator,
subsystem
clock
oscillator
−
When using the high-speed system clock oscillator and subsystem clock
oscillator, wire as follows in the area enclosed by the broken lines in the Figures
5-8 and 5-9 to avoid an adverse effect from wiring capacitance.
•
Keep the wiring length as short as possible.
•
Do not cross the wiring with the other signal lines.
•
Do not route the wiring near a signal line through which a high fluctuating
current
flows.
•
Always make the ground point of the oscillator capacitor the same potential as
V
SS
. Do not ground the capacitor to a ground pattern through which a high
current
flows.
•
Do not fetch signals from the oscillator.
Note that the subsystem clock oscillator is designed as a low-amplitude circuit for
reducing power consumption.
p. 119
Hard
Prescaler
−
When the Ring-OSC clock is selected as the clock supplied to the CPU, the
prescaler generates various clocks by dividing the Ring-OSC oscillator output (f
X
=
240 kHz (TYP.)).
p. 121
The RSTOP setting is valid only when “Can be stopped by software” is set for
Ring-OSC by the option byte.
p. 128
Ring-OSC
−
To calculate the maximum time, set f
R
= 120 kHz.
p. 129
Selection of the CPU clock cycle division factor (PCC0 to PCC2) and switchover
from the high-speed system clock to the subsystem clock (changing CSS from 0
to 1) should not beset simultaneously.
Simultaneous setting is possible, however, for selection of the CPU clock cycle
division factor (PCC0 to PCC2) and switchover from the subsystem clock to the
high-speed system clock (changing CSS from 1 to 0).
p. 130
Chapter 5
Soft
CPU
clock
−
While the CPU is operating on Ring-OSC, setting the following values is
prohibited.
•
CSS, PCC2, PCC1, PCC0 = 0, 0, 1, 0
•
CSS, PCC2, PCC1, PCC0 = 0, 0, 1, 1
•
CSS, PCC2, PCC1, PCC0 = 0, 1, 0, 0
p. 130