Commodore Amiga - Page 281

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POWER ••• 7 PIN STRAIGHT (.156) (J14)
1 -5
2 +12
3 gnd
4 gnd
5 +5
6 +5
7 tick
JOY STICKS ••• DB9 male (J11 = right J12 = left)
1 FORWARD' (MOUSE V)
2 BACK* (MOUSE H)
3 LEFT* (MOUSE VQ)
4 RIGHT' (MOUSE HQ)
5 POT X (or button 3 if used )
6
FIRE' (or button 1)
7 +5
8 GND
9 POT Y (or button 2 )
The following port power allocation list is based on many things,
including known peripheral requirements and existing power supply
capabilities. These numbers are maximums for each port when used
independently, but the numbers can be accumulated (except for
joysticks) when a particular system configuration will guarantee
th9~ it exclusively uses more than one port.
The power pins of both joystick ports are tied together and to
a current limited +5 supply. At present, the current limit is set
at 700 ma peak with a 400 ma foldback at steady state short
circuit conditions. The combined utilization of both ports is
limited to 250 ma to insure a minimum voltage drop at the pins.
PORT
+5(ma) +12(ma)
-5(ma)
--------------
RF modulator
60
RGB
300
175 50
Serial 100 50 50
External disk 270 160
Parallel
100
Expansion
1000 50
50
Joystick 0
125
Joystick l.
125
""""""" PART 2 - MDRE OUTSIDE WORLD """"""""""
PARALLEL INTERFACE CONNECTOR SPECIFICATION
The 25-pin D-type connector with pins (DB25P=male) at the rear of the
Amiga is nominally used to interface to parallel printers. In this
capacity, data flows from the Amiga to the printer. This interface
may also be used for input or bidirectional 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 ASSIGNMENT (J8)
PIN NAME DIR NOTES
1 DRDY' 0 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
2
DO
3
D1
4
D2
5 D3
6 D4
7 D5
8 D6
9
D7
10
ACK'
11 BUSY
12 POUT
13 SEL
14 GND
15 GND
16 GND
17 GND
18 GND
19 GND
20 GND
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
I/O
I/O
I/O
diagrams in the following section.
DO-D7 comprise an eight-bit bidirectional bus for
communication with parallel devices,
nominally, a printer.
Output-data-acknowledge from parallel device in
output mode, used in conjunction with DRDY' (pin 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 programned to
conditionally generate a level 2 interrupt to the
68000 whenever the ACK* input goes active.
This is a general purpose I/O pin shorted to a ..
serial data I/O pin (serial clock on pin 12) .
Note: Nominally used to indicate printer buffer full.
This is a general purpose I/O pin shorted to a
serial clock I/O pin (serial data on pin 11).
Note: Nominally used to indicate printer paper out.
This is a general purpose I/O pin.
Note: nominally a select output from the parallel
device to the Amiga.