Epson LQ-2550 Technical Manual page 254

Pin
Terminal 1/0
No.
34
AN 1
35
36
37
3 8
3 9
4 0
41
AV
4 3
CC
42
V A
R E F
—
33 AV
SS
47
54
55
62
46 ALE
44 RD
45 WR
29 MODEO
27 MODE 1
28 RESET
x l
31
30
x 2
64
63
32
GND —
Table A-3. PPD781OHG Terminal Functions
Signal
Name
I +35 V line voltage detection
I
printer cover OPEN/CLOSE
detection
I Image scanner signal
I PW sensor signal
I PT sensor signal
I CONDENSED, PAPER SE-
FONT switches signal
I
PLATEN GAP ADJUST,
PITCH switches signal
I L O A D / E J E C T , L I N E F E E D ,
FORM FEED switches signal
I Analog port power supply
(+5 VDC)
o
Analog port reference voltage
Analog port ground
o Upper address (A8 to Al 5)
bus
Lower address (AO to A7)/
data (AO to A7) bus
o
Address latch enable
o Read strobe
o
Write strobe
Mode 3 select (fixed)
I
Address OOOOH to EFFFH
(External)
FFOOH to FFFFH
(Internal RAM)
i
Reset signal
I
External oscillator
(1 2.2 MHz)
I
I + 5 VDC
+ 5 VDC
Ground
Description
and
A-9
Notes
Optional image scanner
Printer mechanism
Printer mechanism
Control panel
Control panel
Control panel
Selected by the ALE signal
REV.-A