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Function
Details of
Function
Electrical
XT1 oscillator
specifications
characteristics
((A) grade
products)
Recommended
oscillator
constants
DC
characteristics
APPENDIX B LIST OF CAUTIONS
Since the CPU is started by the internal high-speed oscillation clock after a reset
release, check the X1 clock oscillation stabilization time using the oscillation
stabilization time counter status register (OSTC) by the user.
oscillation stabilization time of the OSTC register and oscillation stabilization time
select register (OSTS) after sufficiently evaluating the oscillation stabilization time
with the resonator to be used.
When using the XT1 oscillator, wire as follows in the area enclosed by the broken
lines in the above figures 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
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
The XT1 oscillator is designed as a low-amplitude circuit for reducing power
consumption, and is more prone to malfunction due to noise than the X1 oscillator.
Particular care is therefore required with the wiring method when the XT1 clock is
used.
The oscillator constants shown above are reference values based on evaluation in a
specific environment by the resonator manufacturer. If it is necessary to optimize the
oscillator characteristics in the actual application, apply to the resonator
manufacturer for evaluation on the implementation circuit.
When doing so, check the conditions for using the AMPH bit, RMC register, and
whether to enter or exit the STOP mode.
The oscillation voltage and oscillation frequency only indicate the oscillator
characteristic. Use the 78K0R/KE3 so that the internal operation conditions are
within the specifications of the DC and AC characteristics.
The oscillator constants shown above are reference values based on evaluation in a
specific environment by the resonator manufacturer. If it is necessary to optimize the
oscillator characteristics in the actual application, apply to the resonator
manufacturer for evaluation on the implementation circuit.
When doing so, check the conditions for using the RMC register, and whether to
enter or exit the STOP mode.
The oscillation voltage and oscillation frequency only indicate the oscillator
characteristic. Use the 78K0R/KE3 so that the internal operation conditions are
within the specifications of the DC and AC characteristics.
P02 to P04 do not output high level in N-ch open-drain mode.
The maximum value of V
of pins P02 to P04 is V
IH
mode.
For P122/EXCLK, the value of V
external clock mode.
Make sure to satisfy the DC characteristics of EXCLK in
external clock input mode.
User's Manual U17854EJ9V0UD
Cautions
, even in the N-ch open-drain
DD
and V
differs according to the input port mode or
IH
IL
(31/33)
Page
p.760
Determine the
p.762
.
SS
p.762
pp.763
to 766
p.767
p.768
p.770
p.770
855
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