
GENNUM CORPORATION
522 - 45 - 05
19
G
Fig. 11
Audio Clock Input
The
user
(128 fs: 6.144MHz) at the ACLK clock terminal. This clock
must be synchronized with the video signal input to the
GS9023. The audio word clock inputs WCINA and WCINB
must be grounded.
must
input
a
master
audio
clock
Audio Data Output
The serial audio data for channels 1 and 2 are output at the
AOUTA pin. The serial audio data for channels 3 and 4 are
output at the AOUTB pin. Both outputs are synchronized to
the rising edge of ACLK.
The GS9023 can demultiplex 20 or 24 bit audio data
samples. When 24 bit audio samples are detected, the
AUXEN pin and bit
“
A4ON
”
of Host Interface Register #1h
are set HIGH. When 20 bit audio samples are detected the
AUXEN pin and
“
A4ON
”
register bit are set LOW. When
AUXEN and
“
A4ON
”
are LOW, bits 4-7 of the AES/EBU
output data format are set to
“
0
”
. In the non-AES/EBU
formats, bits 0-3 are set to
“
0
”
. See Figure 12
The GS9023 offers five predefined audio data output
formats, selected via the AM[2:0] pins, which are listed in
Table 12 and illustrated in Figure 12. The first four
predefined formats relate to non-AES/EBU audio data while
the fifth format corresponds to the AES/EBU audio format.
During reset, the audio outputs are forced LOW.
The GS9023 supports muting of the audio data outputs. The
output serial audio samples are forced to zero when the
MUTE pin or
“
MUTE
”
bit of Host Interface Register #4h are
set HIGH. The audio data outputs are also muted when
there is no video input signal.
E
S
Empty
Video signal before GS9023
S
Empty
Video signal after GS9023 Removal of Audio Group 1 & Extended Audio Group 1
(ANCI = LOW or "VSEL" = HIGH and "ADEL" = LOW)
E
A
G
A
G
E
A
G
(
A
G
(
E
E
A
G
A
E
A
G
(
A
G
G
(
TABLE 12: Audio Output Formats
FORMATS
WCOUT
AM[2]
AM[1]
AM[0]
AOUT-MODE 0
Active
48kHz
0
0
0
AOUT-MODE 1
Active
48kHz
0
0
1
AOUT-MODE 2
Active
48kHz
0
1
0
AOUT-MODE 3
Active
48kHz
0
1
1
AOUT-AES/EBU
-
1
0
0
Not Used
-
1
0
1
Not Used
-
1
1
0
Not Used
-
1
1
1