Commodore Amiga A2000 - PARALLEL INTERFACE CONNECTOR SPECIFICATION

************** PART 2 MORE OUTSIDE WORLD ********************
PARALLEL INTERFACE CONNECTOR SPECIFICATION
The 25-pin D-type connector with pins (DB25P=male for the A1000,
female for A500/A2000 and IBM compatibles) at the rear of the
Amiga is nominally used to interface to parallel printers. In this
capacity, data flow from the Amiga to the printer. This interface
may be used for input or bi-directional data transfers. The
implementation is similar to Centronics, but the pin assignment and
drive characteristics vary significantly from that specification
(See Pin assignment). Signal names correspond to those used in the
other places in this appendix, when possible.
PARALLEL CONNECTOR PIN ASSIGNNENT (J8)
NAME DIR NOTES
---- --- -----
DRDY* O Output-data-ready signal to parallel device in
output mode, used in conjunction with ACK* (pin
10) for a two-line asynchronous handshake.
Functions as input data accepted from Amiga in
input mode (similar to ACK* in output mode). See
timing diagrams in the following section.
D0 I/O +
Dl I/O |
D2 I/O |
D3 I/O | D0-D7 comprise an eight-bit bidirectional bus
D4 I/O | for communication with parallel devices,
D5 I/O | nominally, a printer.
D6 I/O |
D7 I/O +
ACK* I Output-data-acknowledge from parallel device in
output mode, used in conjunction with DRDY* (pin ÿ
1) for a two-line asynchronous handshake.
Functions as input-data-ready from parallel device
in input mode similar to DRDY* in output mode).
See timing diagrams. The 8520 can be programmed to
conditionally generate a level 2 interrupt to the
68000 whenever the ACK* input goes active.
BUSY I/O This is a general purpose I/O pin also connected
to a serial data I/O pin (serial clock on pin 12).
Note: Nominally used to indicate printer buffer full.
POUT I/O This is a general purpose I/O pin to a serial
clock I/O pin (serial data on pin 11).
Note: Nominally used to indicate printer paper out.
SEL I/O This is a general purpose I/O pin.
Note: nominally a select output from the parallel
device to the Amiga. On the A500/A2000 also shared
with RS232 "ring indicator" signal.
RESET* O Amiga System reset
- 302 Appendix E -