Samsung SRP-350PG - SRP 350 B/W Direct Thermal Printer Service Manual page 49

6 Reference Information
6-1 Semiconductor Base Diagram
6-1-3 Logic ICs
74HC02
/OE
D0
D1
D2
D3 74HC574
D4
D5
D6
D7
GND
6-1-4 Other Semiconductor Chip
Low EMI Spectrum Spread Clock
XIN
XOUT
FS741
REF_OFF
LF
INPUT
DI
H
L
6-4
74HC32
VCC
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
C
Differential Bus Transceivers
VCC
RS0
RS1
VSS
MAX488 DRIVER
OPERATION
Y
H
L
74HC574 FUNCTION TABLE
INPUT
/OC
L
L
L
H
VCC
RO
MAX488
DI
GND
DIFFERENTIAL INPUT
A-B
Z

0.2 V
L V
ID
H -0.2 V < V
 -0.2 V
V
ID
74HC74
C D
H H
H L
L X
X X
Voltage Detect System Reset IC
A
B
Z
Y
MAX488 RECEIVER
< 0.2 V
ID
Samsung Electro-Mechanics
OUTPUT Q
H
L
Q0
Z
OUTPUT
DELAY CATACITOR
GND
N.C
SUPPLY VOLYAGE
OUTPUT
RO
H
?
L