Canon MultiPASS C50, Service Manual

Page: 252 / 272

2.10.2 Structure
a) Centronics uni-directional interface (Compatibility mode)
See
Part 2: Printer, Chapter 1: 2.2 Interface Specifications on page 1-5
.
b) Bi-Centronics Interface (Nibble mode)
In Nibble mode, the host computer sends data to the facsimile using the 8-bit data line as used for the
Centronics interface. However, the facsimile transfers data to the host computer using the four status
signal lines by dividing 8-bit data into 4 bits and sending them.
b-1) Pin Assignment
The following table lists the signals and input/output status of the pin assignments used for parallel
communication.
1. All RETs are connected to GND.
2. These signals are valid only in Epson LQ printer control mode.
3. The level is raised to +5.0V at 3.3k register.
4. The level is raised to +5V at 390 register.
Part 2: Printer
2-12
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
No.
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Signal
(STROBE)
HOSTCLK
(DATA 1)
(DATA 2)
(DATA 3)
(DATA 4)
(DATA 5)
(DATA 6)
(DATA 7)
(DATA 8)
(ACKNLG)
PTRCLK
(BUSY) PTRBUSY
(P.E.)
ACK DATA REQ
(SELECT) xflog
(AUTO FEED XT
2
)
HOST BUSY
NO CONNECTION
GND
GND
PERIPHERAL
LOGIC HIGH 4
Signal
STROBE-RET
DATA 1-RET
DATA 2-RET
DATA 3-RET
DATA 4-RET
DATA 5-RET
DATA 6-RET
DATA 7-RET
DATA 8-RET
ACKNLG-RET
BUSY-RET
PAPER END-RET
INIT
ERROR
DATA AVAILABLE
GND
NO CONNECTION
+5.0V
3
SELECT IN
2
I/O
IN
IN/OUT
IN/OUT
IN/OUT
IN/OUT
IN/OUT
IN/OUT
IN/OUT
IN/OUT
OUT
OUT
OUT
OUT
I/O
IN
OUT
OUT