Canon MultiPASS C50 Service Manual page 252

Part 2: Printer
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.
No.
1
2
3
4
5
6
7
8
9
10
11 (BUSY) PTRBUSY
12
ACK DATA REQ
13 (SELECT) xflog
14 (AUTO FEED XT
15 NO CONNECTION
16
17
18
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.
I/O
Signal
IN
(STROBE)
HOSTCLK
IN/OUT
(DATA 1)
IN/OUT
(DATA 2)
IN/OUT
(DATA 3)
IN/OUT
(DATA 4)
IN/OUT
(DATA 5)
IN/OUT
(DATA 6)
IN/OUT
(DATA 7)
IN/OUT
(DATA 8)
OUT
(ACKNLG)
PTRCLK
OUT
OUT
(P.E.)
OUT
)
2
HOST BUSY
GND
GND
PERIPHERAL
LOGIC HIGH
4
Signal
No.
STROBE-RET
19
DATA 1-RET
20
DATA 2-RET
21
DATA 3-RET
22
DATA 4-RET
23
DATA 5-RET
24
DATA 6-RET
25
DATA 7-RET
26
DATA 8-RET
27
ACKNLG-RET
28
BUSY-RET
29
PAPER END-RET
30
INIT
31
ERROR
32
DATA AVAILABLE
GND
33
NO CONNECTION
34
+5.0V
3
35
SELECT IN
36
2-12
I/O
IN
OUT
OUT
2