UPD75104 Datasheet, PDF (45/70 Pages) NEC – 4-BIT SINGLE-CHIP MICROCOMPUTER

µPD75104, 75106, 75108
10.5 PUSHBUTTON TELEPHONE
Hook switch
Transmitter/
receiver/
speaker
selector
Transmitter/
receiver
Communication
circuit
To main
equipment
High-
current
output
LED
indicator
TO
µ PD75108
Key
matrix
Filter
SIO
MPX
Call sound
Speaker
amplifier
Microphone
amplifier
Speaker
Microphone
µ PD7228G
LCD
controller/
driver
LCD indicator
Data
receiver
circuit
Data
transmitter
circuit
10.6 DISPLAY PAGER
Filter
µ PD75108
INT
Code ROM
TO
Piezoelectric
buzzer
RAM
µPD4464
High-
current
output
Switch
LED indicator
Comparator
input
SIO
LCD controller/
driver
µ PD7228/7229
Battery
check
LCD indicator
45