
APPENDIX B LIST OF CAUTIONS
User’s Manual U17894EJ9V0UD
932
(33/35)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
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 VSS.
Do not ground the capacitor to a ground pattern through which a high current flows.
Do not fetch signals from the oscillator.
p.831
XT1 oscillator
characteristics
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.
p.831
pp.832,
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/KG3 so that the internal operation conditions are
within the specifications of the DC and AC characteristics.
to 835
Recommended
oscillator
constants
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/KG3 so that the internal operation conditions are
within the specifications of the DC and AC characteristics.
p.836
P02 to P04, P43, P45, P142 to P144 do not output high level in N-ch open-drain
mode.
pp.837,
838
The maximum value of VIH of pins P02 to P04, P43, P45, and P142 to P144 is VDD,
even in the N-ch open-drain mode.
pp.839,
840
DC
characteristics
For P122/EXCLK, the value of VIH and VIL differs according to the input port mode or
external clock mode.
Make sure to satisfy the DC characteristics of EXCLK in
external clock input mode.
pp.839,
840
CLKOUT output is not used during CLKOUT asynchronous operation, but a CPU
wait occurs according to the setting of bits 4 and 5 (EW0, EW1) of the memory
expansion mode control register (MEM). When fCLK is sufficiently high, insert a wait
by setting the EW0 and EW1 bits.
p.861
Hard
External bus
interface
Do not use the WAIT pin during CLKOUT asynchronous operation.
Use the separate bus mode during CLKOUT asynchronous operation.
p.861
Chapter
3
0
Soft
Electrical
specifications
((A) grade
products)
During
communication
at same potential
(UART mode)
(dedicated baud
rate generator
output)
Select the normal input buffer for RxDi and the normal output mode for TxDi by using
the PIMg and POMg registers.
p.863