CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U16315EJ1V0UD
112
5.4 System Clock Oscillator
5.4.1 X1 oscillator
The X1 oscillator oscillates with a crystal resonator or ceramic resonator (Standard: 8.38 MHz, 10 MHz when
REGC pin is directly connected to V
DD
) connected to the X1 and X2 pins.
An external clock can be input to the X1 oscillator when the REGC pin is directly connected to V
DD
. In this case,
input the clock signal to the X1 pin and input the inverse signal to the X2 pin.
Figure 5-9 shows the external circuit of the X1 oscillator.
Figure 5-9. External Circuit of X1 Oscillator
(a) Crystal, ceramic oscillation
(b) External clock
IC
X1
X2
Crystal resonator or
ceramic resonator
V
SS
External
clock
X1
X2
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 when the REGC pin is directly connected to V
DD
. In
this case, input the clock signal to the XT1 pin and the inverse signal to the XT2 pin.
Figure 5-10 shows an external circuit of the subsystem clock oscillator.
Figure 5-10. External Circuit of Subsystem Clock Oscillator
(a) Crystal oscillation
(b) External clock
XT2
IC
XT1
32.768
kHz
XT1
XT2
External
clock
V
SS
Cautions are listed on the next page.