UPD75518 NEC, UPD75518 Datasheet - Page 56

• Manufacturer Part Number: UPD75518
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

56
(5) System clock oscillator
The main system clock oscillator operates with a crystal (6.0 MHz standard) or ceramic resonator
connected to the X1 and X2 pins.
An external clock can also be input.
The subsystem clock oscillator operates with a crystal resonator (32.768 kHz standard) connected to the
XT1 and XT2 pins.
An external clock can also be input.
A caution on connecting the oscillator is described on the next page.
(a) Crystal/ceramic oscillation
(a) Crystal oscillation
Crystal
or ceramic
resonator
32.768 kHz
Fig. 4-14 External Circuitry for the Main System Clock Oscillator
Fig. 4-15 External Circuitry for the Subsystem Clock Oscillator
X1
X2
XT1
XT2
PD75518(A
PD75518(A)
)
External
clock
External
clock
(b) External clock
(b) External clock
Open
X1
X2
PD75518(A)
XT1
XT2
PD75518(A)
PD75518(A)