5002C-CGT Datasheet, PDF (6/23 Pages) List of Unclassifed Manufacturers – Dual SCART A/V Switch

AVPro^® 5002C
Dual SCART A/V Switch
SCART AUDIO SWITCHING
The audio inputs are considered to be associated
with the respective video inputs. As a result, the
video selection determines which audio signals will
be switched to a given SCART output. Refer to the
serial port register table for more information. Also
see the audio switching block diagram shown in
Figure 2.
The 5002C provides inputs for the auxiliary audio
source (Aux_Lin/Aux_Rin), a stereo DAC associated
with the video encoder inputs (Lin/Rin), and inputs
from the TV SCART (TV_Lin/TV_Rin).
TV AUDIO OPERATION
The audio source for the TV port is selected in
concert with the video source using the three (3)
LSBs of Register 1. The selected audio signals are
input to internal multiplexers that allow the user to
select between mono and stereo output options. Bits
4 and 5 of Register 3 control the stereo/mono
selection according to the following table:
Bit 1
0
0
1
1
Bit 0
0
1
0
1
TV left source
left input
left + right
left input
right input
TV right source
right input
left + right
left input
right input
At power-up, these bits default to 00 putting the
device in the stereo mode.
Volume Control: The left and right TV audio
channels can be selected to pass through volume
control circuits. Each volume control circuit is formed
by a serially connected amplifier and attenuator pair.
The amplifier is programmed by register 4, bit 2( “0”
for 0 dB and “1” for 6 dB gains ). The attenuator is
programmed by the lower 6 bits of register 0(
“xx000000” for 0 dB and “xx111111” for –63 dB
attenuations, in –1 dB steps ). Only the lower 5 bits
are guaranteed for accuracy( 0 to –31 dB ).
DAC Input Gain (Lin/Rin): To support audio DACs
that have a limited output range, the 5002C provides
programmable gain amplifiers on the Lin and Rin
inputs. The gain is set by Bits 2 and 3 of Register 3,
according to the following table:
Bit 3
0
0
1
1
Bit 2
0
1
0
1
Gain
Gain = 0 dB
Gain = 6 dB
Gain = 9 dB
Gain = 11.6 dB
TV SCART Audio Outputs: The first pair of signals
is labeled TV_Lout and TV_Rout on the block
diagram. TV_Lout and TV_Rout are typically used to
drive the TV SCART audio pins. These outputs also
have an internal multiplexer that allows the user to
select TV audio either before or after the internal
volume control function. When Bit 0 in Register 4 is
set low (0), the volume control is used. When this bit
is set high (1), the volume control is bypassed. The
power-up default state is volume control active.
TV Audio Line Outputs: The second pair of signals
is labeled Lout and Rout on the block diagram. Lout
and Rout are standard line outputs. The Lout/Rout
outputs have an internal multiplexer that allows the
user to select TV audio either before or after the
internal volume control function. When Bit 1 in
Register 4 is set low (0), the volume control is used.
When this bit is set high (1), the volume control is
bypassed. The power-up default state is volume
control active. In addition, the audio inputs from the
TV SCART connector (TV_Lin/TV_Rin) can be
switched to the line outputs. This is controlled by bit-
3 of Register 4. Setting this bit low (0) is the normal
operation where the line outputs follow the TV
SCART outputs. Setting this bit high (1) will switch
the line outputs to the audio source on the
TV_Lin/TV_Rin inputs.
RF Mono Output: The TV_Lout and TV_Rout
signals are also summed internally to generate a
mono audio signal for an external RF modulator.
This output is labeled Mod_mono. The internal
summing circuit is after the volume control mux so
the audio control on this output will be the same as
that selected for the TV_Lout and TV_Rout outputs.
TV Audio Mute: A mute function is provided for all
TV audio outputs. The mute function is controlled by
setting Bit 6 in Register 0. When this bit is set to a
high state (1), all TV audio outputs are muted. This
will be the default condition at power-up. When the
bit is set to a low state (0), the audio path will be in
normal operating mode. This bit can be set
independent of the volume control such that the
outputs can be muted before any change in volume,
or any switching of audio sources.
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