upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 499

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

Electrical
specifications
(standard
products, (A)
grade
products),
Electrical
specifications
((A1) grade
products)
Recommend
ed soldering
conditions
Wait
Function
High-speed
system clock
(crystal/
ceramic)
oscillator
Recommended
oscillator
constants
Subsystem clock
oscillator
Details of
Function
−
−
When using the crystal/ceramic 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
• Always make the ground point of the oscillator capacitor the same potential
• Do not ground the capacitor to a ground pattern through which a high
• Do not fetch signals from the oscillator.
Since the CPU is started by the internal oscillation clock after reset, check the
oscillation stabilization time of the high-speed system clock using the
oscillation stabilization time counter status register (OSTC). Determine the
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.
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. The oscillation voltage and oscillation frequency only indicate the
oscillator characteristic. Use the 78K0/KD1+ so that the internal operation
conditions are within the specifications of the DC and AC characteristics.
When using the subsystem clock oscillator, wire as follows in the area
enclosed by the broken lines in the above figure 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
• Always make the ground point of the oscillator capacitor the same potential
• Do not ground the capacitor to a ground pattern through which a high
• Do not fetch signals from the oscillator.
The subsystem clock oscillator is designed as a low-amplitude circuit for
reducing power consumption, and is more prone to malfunction due to noise
than the high-speed system clock oscillator. Particular care is therefore
required with the wiring method when the subsystem clock is used.
Do not use different soldering methods together (except for partial heating).
When the CPU is operating on the subsystem clock and the high-speed
system clock is stopped (MCC = 1), do not access the registers listed above
using an access method in which a wait request is issued.
current flows.
as V
current flows.
current flows.
as V
current flows.
APPENDIX D LIST OF CAUTIONS
SS
SS
.
.
User’s Manual U16962EJ3V0UD
Cautions
pp. 428,
444
pp. 428,
444
p. 429
pp. 430,
445
pp. 430,
445
p. 459
p. 461
Page
(23/23)
499