System Clock Oscillator - NEC mPD784225 Series User Manual

4.4 System Clock Oscillator

4.4.1 Main system clock oscillator
The main system clock oscillator oscillates with a crystal resonator or a ceramic resonator (standard: 12.5 MHz)
connected to the X1 and X2 pins.
External clocks can be input to the main system clock oscillator. In this case, input a clock signal to the X1 pin
and an antiphase clock signal to the X2 pin.
Figure 4-6 shows an external circuit of the main system clock oscillator.
Figure 4-6. External Circuit of Main System Clock Oscillator
(a) Crystal or ceramic oscillation
V
SS1
Crystal resonator
or
ceramic resonator
100
CHAPTER 4 CLOCK GENERATOR
X2
X1
V
SS1
User's Manual U12697EJ3V0UM
(b) External clock
X2
External
X1
clock
µ
PD74HCU04