System Clock Oscillator; X1 Oscillator; Subsystem Clock Oscillator - NEC 78K0 User Manual

5.4 System Clock Oscillator

5.4.1 X1 oscillator

The X1 oscillator oscillates with a crystal resonator or ceramic resonator (Standard: 10 MHz) connected to the X1
and X2 pins.
External clocks can be input to the X1 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 X1 oscillator.
(a) Crystal, ceramic oscillation
Crystal resonator or
ceramic resonator

5.4.2 Subsystem clock oscillator

The subsystem clock oscillator oscillates with a crystal resonator (Standard: 32.768 kHz) connected to the XT1
and XT2 pins.
External clocks can be input to the subsystem clock oscillator. In this case, input the clock signal to the XT1 pin
and the inverse signal to the XT2 pin.
Figure 5-9 shows examples of the external circuit of the subsystem clock oscillator.
Figure 5-9. Examples of External Circuit of Subsystem Clock Oscillator
(a) Crystal oscillation
Cautions are listed on the next page.
106
CHAPTER 5 CLOCK GENERATOR
Figure 5-8. Examples of External Circuit of X1 Oscillator
V
SS
X1
X2
V
SS
XT1
32.768
kHz
XT2
User's Manual U16227EJ2V0UD
(b) External clock
External
X1
clock
X2
(b) External clock
External
clock
XT1
XT2