Commodore Amiga A500 Technical Reference Manual page 112

AUDIO SIGNALS
Raw
Audio
Filter Cutoff (/LED)
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 t o
be in place at fc
=
6 kHz or so, t o 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 t o cut out the two pole low pass filter on the stan-
dard audio channels. When asserted, the filter is in place; when ne-
gated the filter is bypassed. This is an input t o this Video connector,
useful t o allow any AudioNideo card t o monitor the audio filtering
state. Pin 31 .
VIDEO SLOT PINOUTS The original A2000 video slot is a 36 pin edge connector, the same
type as used on the A2000's 1 6 bit IBM style bus extension.
PIN
1
3
5
7
9
11
1 3
1
S
1 7
1 9
2 1
2 3
2 5
2 7
2 9
3 1
33
35
Signal
Reserved for Expansion
Left Audio Out
Reserved for Expansion
Analog Red
Video Ground
Analog Green
Video Ground
Analog Blue
Video Ground
/C4 Clock
Video Ground
B 0
=
D1 (47 Ohm)
B 3
=
DB ( 4 7 Ohm)
G3
=
DG (47 Ohm)
R 3
=
DR (47 Ohm)
-5 VDC
XCLK
Reserved for Expansion
PIN
2
4
6
8
1 0
1 2
1 4
1 6
1 8
2 0
2 2
2 4
2 6
2 8
30
3 2
34
36
Signal
Reserved for Expansion
Right Audio Out
+
5 VDC
+
5 VDC
+
1 2 VDC
Video Ground
/CSYNC
IXCLKEN
BURST
Video Ground
IHSYNC
(47
Ohm)
Video Ground
NSYNC (47 Ohm)
COMP SYNC (Analog)
IPIXELSW (47 Ohm)
Video Ground
/C1 Clock
Reserved for Expansion