Commodore Amiga A500 Technical Reference Manual page 109

AUDIO SIGNALS
Raw Audio
Filter Cutoff (/LED)
VIDEO SLOT PINOUTS
The B2000 Extended Video Slot offers a few additional audio sig-
nals.
These are the left and right audio channels before they're passed
through the low pass filter on output For many applications, the
audio sampling rate is low, and as such requires a low pass filter to
be in place at fc = 6 kHz or so, to prevent audio aliasing. However.
higher sampling rates are possible, and in such cases, a much higher
filtering frequency is required for best possible sound. This raw
audio, left on pin 33 and right on pin 35. is buffered but unfiltered.
This is the /LED port line. In the B2000. as per the A500
convention, this signal is used to cut out the two pole low pass filter
on the standard audio channels. When asserted, the filter is in place;
when negated the filter is bypassed. This is an input to this Video
connector, useful to allow any Audio/Video card to monitor the
audio filtering state. Pin 31.
The original A2000 video slot is a 36 pin edge connector, the same
type as used on the A2000's 16 bit IBM style bus extension.
PI Signal
N
1 Reserved for Expansion
3 Left Audio Out
5 Reserved for Expansion
7 Analog Red
9 Video Ground
11 Analog Green
13 Video Ground
15 Analog Blue
17 Video Ground
19 /C4 Clock
21 Video Ground
23 BO = Dl (47 Ohm)
25 B3 = DB (47 Ohm)
27 G3 - DG (47 Ohm)
29 R3 - DR (47 Ohm)
31 -5VDC
33 XCLK
35 Reserved for Expansion
106
PIN Signal
2 Reserved for Expansion
4 Right Audio Out
6 + 5VDC
8 + 5VDC
10 + 12VDC
12 Video Ground
14 /CSYNC
16 /XCLKEN
18 BURST
20 Video Ground
22 /HSYNC (47 Ohm)
24 Video Ground
26 /VSYNC (47 Ohm)
28 COMP SYNC (Analog)
30 /P1XELSW (47 Ohm)
32 Video Ground
34 /Cl Clock
36 Reserved for Expansion