System Clock Oscillator; X1 Oscillator; Subsystem Clock Oscillator; Examples Of External Circuit Of X1 Oscillator - NEC 78K0 User Manual

6.4

System Clock Oscillator

6.4.1

X1 oscillator

The X1 oscillator oscillates with a crystal resonator or ceramic resonator (Standard: 8.38 MHz, 10 MHz when
REGC pin is connected directly to V
An external clock can be input to the X1 oscillator when the REGC pin is connected directly to V
input the clock signal to the X1 pin and input the inverse signal to the X2 pin.
Figure 6-8 shows examples of the external circuit of the X1 oscillator.
(a) Crystal, ceramic oscillation
Crystal resonator or
ceramic resonator
6.4.2

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 when the REGC pin is connected directly to V
this case, input the clock signal to the XT1 pin and the inverse signal to the XT2 pin.
Figure 6-9 shows examples of external circuit of the subsystem clock oscillator.
Figure 6-9. Examples of External Circuit of Subsystem Clock Oscillator
(a) Crystal oscillation
Cautions are listed on the next page.
150
CHAPTER 6 CLOCK GENERATOR
) connected to the X1 and X2 pins.
DD
Figure 6-8. Examples of External Circuit of X1 Oscillator
V
SS
X1
X2
V
SS
XT1
32.768
kHz
XT2
User's Manual U15947EJ2V0UD
(b) External clock
External
X1
clock
X2
*
(b) External clock
External
clock
. In this case,
DD
. In
DD
XT1
XT2