upd78f0114hgb-8es-a Renesas Electronics Corporation., upd78f0114hgb-8es-a Datasheet - Page 105

• Manufacturer Part Number: upd78f0114hgb-8es-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
(2) External RC oscillator
The following two high-speed system clock oscillators are available.
High-speed system clock oscillation can be selected using the option byte. Refer to CHAPTER 22 OPTION BYTE
Cautions are listed on the next page.
The crystal/ceramic oscillator oscillates with a crystal resonator or ceramic resonator connected to the X1 and X2
pins.
External clocks 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 examples of the external circuit of the crystal/ceramic oscillator.
The external RC oscillator is oscillated by the resistor (R) and capacitor (C) connected across the CL1 and CL2
pins.
An external clock can also be input to the circuit. In this case, input the clock signal to the CL1 pin, and input the
inverted signal to the CL2 pin.
Figure 5-9 shows the external circuit of the external RC oscillator.
Crystal/ceramic oscillator: Oscillates a clock of f
External RC oscillator: Oscillates a clock of f
(a) Crystal, ceramic oscillation
(a) RC oscillation
Crystal resonator or
ceramic resonator
Figure 5-8. Examples of External Circuit of Crystal/Ceramic Oscillator
C
R
Figure 5-9. External Circuit of External RC Oscillator
V
CL1
CL2
SS
V
X1
X2
SS
CHAPTER 5 CLOCK GENERATOR
User’s Manual U16961EJ4V0UD
XP
= 3 to 4 MHz
XP
= 2 to 16 MHz
External
clock
External
clock
(b) External clock
(b) External clock
X1
X2
CL1
CL2
105