Bi-Directional Centronics Interface - Canon MultiPASS C530 Service Manual

MultiPASS C530/C560 Chapter 2: Technical Reference

8.4.2 Bi-directional centronics interface

a) Specifications
This parallel interface performs data transmission 8 bits (1 byte) at a time, and conforms to TTL.
Interface Type
IEEE P1284-B/Bi-directional parallel
Data Transmission
8 bit parallel interface (IBM PC or compatible machine)
Simultaneous Signal
STROBE signal from the computer
Handshake
BUSY/ACKLG
Interface Connectors
Printer side
Cable side
Recommended Interface Cable
Type
Materials
Length
Signal Voltage Level
Low level
High level
b) Interface Functions
This machine supports 3 bi-directional Centronics modes - compatible mode, nibble mode, and ECP
mode. These are included in IEEE-P1284 D2.00, which was published on September 10, 1993. Where
the host computer supports ECP mode, this machine will transfer data in ECP mode. When the host
computer does not support ECP mode, this machine will transfer data in compatible mode and nibble
mode. Some host computers must have ECP mode set.
Compatible Mode
This mode conforms to conventional Centronics interfaces. The host computer transfers 8 bit-data (in
sequential direction) a peripheral machine in 8 data lines.
Nibble Mode
A peripheral machine transfers data to the host computer with this mode. The 8-bit data is divided into 2
4-bit units, and transfers the 4-bit data to the host computer 1 unit at a time by 4 control lines.
Bi-directional transfer can be accomplished by simultaneously using both of the methods mentioned
above - compatible mode (sequential direction transfer), and nibble mode (reverse direction transfer).
ECP Mode
ECP stands for Extended Compatibility Port. High-speed data transfer can be accomplished with ECP
mode. Data can be transferred faster than in nibble mode because data lines can be used in both
directions without changing modes. Optionally, transfer of compressed data can also be done.
Amphenol 57-40360 or compatible
Amphenol 57-30360 or compatible
Twisted-pair shield cable
AWG No. 28 or larger
Up to 6.56 feet (2.0 m)
0.0V to +4V
+2.4V to 5.0V
2-68