Commodore Amiga - Page 285

CONNECTOR PIN USAGE FOR PROPORTIONAL INPUTS
PIN
1
2
3
4
5
6
7
8
9
MNEMONIC
Unused
Unused
LBUT*
RBUT*
POTX
Unused
+5V
Ground
POT.(
DESCRIPTION
Left button
Right button
X analog in
125ma max, 200 ma surge
Y analog in
HARDWARE REGISTER/NOTES
See Digital Joystick
See Digital Joystick
POT[0/l]DAT<7:0>, POTOO, POTINP
POT[O,l]DAT<15:8>, POTOO, POTINP
CAME PORT INTERFACE TO LIGHT PEN
A light pen is an optoelectronic device Whose light-sensitive portion
is placed in proximity to a CRT. As the electron beam sweeps past the
light pen, a trigger pulse is generated Which can be enabled to latch the
horizontal and vertical beam positions. There is no hardware bit to
indicate this trigger, but this can be determined in the two ways
as shown in chapter 8, "Interface Hardware."
Light pen position is usually read during blanking, but MAY be available
prior to that.
CONNECTOR PIN USAGE FOR LIGHT PEN INPUTS
PIN
MNEMONIC
DESCRIPTION
HARDWARE REGISTER/NOTES
1 Unused
2 Unused
3 Unused
4 Unused
5
LPENPR*
Light pen pressed See Proportional Inputs
6 LPENTG*
Light pen trigger VPOSR, VHPOSR
7
+5V 125ma max, 200 ma surge Both ports
8
Ground
9
Unused
EXTERNAL DISK INTERFACE CONNECTOR SPECIFICA.TION
The 23-pin D-type connector with sockets (OB23S) at the rear of the
Amiga is nominally used to interface to MFM devices.
EXTERNAL DISK CONNECTOR PIN ASSIGNMENT (J7)
PIN NAME DIR
1
ROY* I/O
2 DKRD* I
3 GND
4 GND
5 GND
6 GND
7 GND
8 MTRXD* OC
9 SEL2B* OC
10 DRESS* OC
11 CHNG* I/O
12
+SV
13 SIDEB* 0
14
WPRO*
I/O
15
TKO *
I/O
16
DKWEB*
OC
17 DKWDB* OC
18 STEPB* OC
19 DIRB OC
20 SEL3B* OC
21 SELIS*
OC
22 INDEX*
I/O
23 +12V
NOTES
If motor on, indicates disk installed and up to
speed. If motor not on, identification mode. See
below.
MFM input data to Amiga.
Motor on data, clocked into drive's motor-on
flip-flop by the active transition of SELxB*.
Guaranteed setup time is 1.4 usec.
Guaranteed hold time is 1.4 usec.
Select drive 2
Amiga
system reset. Drives should reset their
motor-on flip-flops and set their write-protect
flip-flops.
Note: Nominally used as an open collector input.
Drive's change flop is set at power up or when no
disk is not installed. Flop is reset when drive is
selected and the head stepped, but only if a disk
is installed.
270 ma maximum; 410 ma surge
When below 3.7SV, drives are required to reset
their motor-on flops, and set their write-protect
flops.
Side 1 if active, side 0 if inactive
Asserted by selected, write-protected disk.
Asserted by selected drive when read/write head
is positioned over track O.
Write gate (enable) to drive.
MFM output data from Amiga.
Selected drive steps one cylinder in the direction
indicated by DIRB.
Direction to step the head. Inactive to step
towards center of disk (higher-nwnbered tracks) •
Select drive 3.
Select drive 1.
Index is a pulse generated once per disk revolution,
between the end and beginning of cylinders. The
8520
can be programmed to conditionally generate a
level 6 interrupt to the 68000 whenever the INDEX*
input goes active.
160 ma maximum; 540 ma surge.