NEC PD754144 - Manual (Page 28)

CHAPTER 2 PIN FUNCTIONS
28 User’s Manual U10676EJ3V0UM
2.2.8 AV
REF
... input pin shared with port 6
This is a reference voltage input pin. An analog reference voltage for the programmable threshold port is input.
2.2.9 CL1 and CL2 (
µPD754144 only)
These pins are used to connect the RC oscillator resistor (R) and capacitor (C) of the system clock oscillator.
No external clock can be input.
RC oscillation
µ PD754144
V SS
CL2
CL1
C
R
2.2.10 X1 and X2 (
µPD754244 only)
These pins connect a crystal/ceramic oscillator for system clock oscillation.
An external clock can also be input to these pins.
(a) Ceramic/crystal oscillation (b) External clock
2.2.11 RESET
This pin inputs an active-low reset signal.
The RESET signal is an asynchronous input signal and is asserted when a signal with a specific low-level width
is input to this pin regardless of the operating clock. The RESET signal takes precedence over all the other operations.
This pin can not only be used to initialize and start the CPU, but also to release the STOP and HALT modes.
The RESET pin is a Schmitt-triggered input pin.
This pin can be connected to an internal pull-up resistor by a mask option.
ExternaI
clock
PD754244 µ
X1
X2
Crystal resonator
or
ceramic resonator
V
SS
X1
X2
(4.194304 MHz TYP.)
µ PD754244