Rc Oscillation External Circuit; Crystal/Ceramic Oscillation External Circuit - NEC PD754144 User Manual

(2) System clock oscillator
(a) µ PD754144 (RC oscillation)
The system clock oscillator oscillates by means of a resistor (R) and capacitor (C) connected to the CL1
and CL2 pins.
An external clock cannot be input for RC oscillation.
The relationship between the output frequency of the system clock oscillator (f
capacitance (C) is as follows.
1
f =
CC
2RC
Cautions f
CC
temperature.
(b) µ PD754244 (Crystal/ceramic oscillation)
The system clock oscillator oscillates by means of crystal or ceramic resonator connected to the X1 and
X2 pins (6.0 MHz or 4.19 MHz TYP.).
An external clock can also be input.
Figure 6-17. Crystal/Ceramic Oscillation External Circuit
(i) Crystal/ceramic oscillation
Crystal or ceramic
resonator
108
CHAPTER 6 PERIPHERAL HARDWARE FUNCTION
may have a frequency deviation due to fluctuation of the supply voltage or
Figure 6-16. RC Oscillation External Circuit
µ
PD754244
X1
X2
V
SS
User's Manual U10676EJ3V0UM
µ
PD754144
CL1
CL2
V
SS
(ii) External clock
External
clock
), resistance (R), and
CC
µ
PD754244
X1
X2