UPD78F0138 NEC, UPD78F0138 Datasheet - Page 127

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

Cautions 1. When using the X1 oscillator and subsystem clock oscillator, wire as follows in the area
Remark When using the subsystem clock, replace X1 and X2 with XT1 and XT2, respectively. Also, insert
Figure 5-10 shows examples of incorrect resonator connection.
resistors in series on the XT2 side.
Note that the subsystem clock oscillator is designed as a low-amplitude circuit for reducing
power consumption.
enclosed by the broken lines in the Figure 5-10 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 fetch signals from the oscillator.
(a) Too long wiring
not ground the capacitor to a ground pattern through which a high current flows.
V
Figure 5-10. Examples of Incorrect Resonator Connection (1/2)
SS
X1
CHAPTER 5 CLOCK GENERATOR
X2
User’s Manual U16228EJ2V0UD
V
SS
(b) Crossed signal line
X1
PORT
X2
SS
. Do
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