upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 90

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

5.4 System Clock Oscillator
5.4.1 High-speed system clock oscillator
for details.
(1) Crystal/ceramic oscillator
90
Caution When using the crystal/ceramic oscillator, wire as follows in the area enclosed by the broken
The following two high-speed system clock oscillators are available.
• Crystal/ceramic oscillator: Oscillates a clock of f
• External RC oscillator:
High-speed system clock oscillation can be selected using the option byte. Refer to CHAPTER 20 OPTION BYTE
Figure 5-9 shows examples of incorrect resonator connection.
The crystal/ceramic oscillator oscillates with a crystal resonator or ceramic resonator connected to the X1 and X2
pins.
An external clock can be input to the crystal/ceramic oscillator. In this case, input the clock signal to the X1 pin
and input the inverse signal to the X2 pin.
Figure 5-8 shows the external circuit of the crystal/ceramic oscillator.
lines in the Figure 5-8 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.
ground the capacitor to a ground pattern through which a high current flows.
(a) Crystal, ceramic oscillation
Crystal resonator or
ceramic resonator
Figure 5-8. External Circuit of Crystal/Ceramic Oscillator
Oscillates a clock of f
V
X1
X2
SS
CHAPTER 5 CLOCK GENERATOR
User’s Manual U16846EJ3V0UD
XP
XP
= 2 to 16 MHz
= 3 to 4 MHz
External
clock
(b) External clock
X1
X2
SS
. Do not