GS1503-CFZ Gennum Corp., GS1503-CFZ Datasheet - Page 27

• Manufacturer Part Number: GS1503-CFZ
• Description: HD EMBEDDED AUDIO CODEC
• Manufacturer: Gennum Corp.

1.8 VIDEO SWITCHING LINE SETTING
The video switching point for field 1 and field 2 can be
configured
SW_LNA[12:0] register is used to configure the video
switching line for field 1, and SW_LNB[12:0] to set video
switching line for field 2. In progressive format video
standards, only the SW_LNA[12:0] register is used. The
default settings are line 7 for field 1 and line 569 for field 2
as defined in SMPTE 299M.
The GS1503 will not multiplex any audio data packets in the
line immediately after the video switching point. For
example, with the default setting of line 7 field 1, there will
be no audio data packets in line 8. The next packets will
appear on line 9. Audio control packets will be multiplexed
once per field, two lines after the video switching point (on
line 9, using the previous example). Arbitrary data packets
will not be multiplexed in the two lines following the video
switching point .
Register Settings
1.9 MULTIPLEX CASCADE MODE
Two GS1503 devices can be cascaded in series to allow up
to 16 channels of audio to be multiplexed (only one device
requires CASCADE to be set HIGH). Figure 24 shows the
cascade architecture for a 16-channel system. To configure
Register Settings
Group 1
Group 2
Audio
Audio
SW_LNA[12:0]
SW_LNB[12:0]
CASCADE
NAME
NAME
Y/C b /C r [19:0]
Audio Channels 1 & 2
Audio Channels 3 & 4
Audio Channels 5 & 6
Audio Channels 7 & 8
via
the
Video Field 1 switching point setting
Video Field 2 switching point setting
Cascade enable (1: Enabled)
GS1503
VIN[19:0]
AIN1/2
AIN3/4
AIN5/6
AIN7/8
CASCADE
Fig. 24 Multiplexing 16 Channels of Audio using Cascade Architecture
Host
GS1503
DESCRIPTION
DESCRIPTION
VOUT[19:0]
Interface.
Group 3
Group 4
Audio
Audio
The
27 of 83
Y/C b /C r [19:0]
Audio Channels 9 & 10
Audio Channels 11 & 12
Audio Channels 13 & 14
Audio Channels 15 & 16
NOTE: The SMPTE 299M standard defines the video
switching point as lines 7 and 569. If the SW_LNA[12:0] and
SW_LNB[12:0] registers are programmed with values other
than lines 7 and 569, the output of the GS1503 is not
guaranteed to be compatible with all HD audio demultiplex
systems. With non-SMPTE 299M compliant switch line
settings, the user should avoid inputting a video data
stream to the GS1503, which already contains embedded
audio data and control packets.
For reliable operation, non-SMPTE 299M compliant video
data streams with embedded audio should not be used in
conjunction with the GS1503 in Multiplex Mode.
the GS1503 for cascade mode, the CASCADE external pin
or CASCADE bit 7 of Host Interface register 014h is set
HIGH. When set HIGH, the GS1503 will default to audio
groups 3 and 4. When set LOW, the GS1503 will default to
audio groups 1 and 2.
ADDRESS
ADDRESS
+3.3V
004
005
002
003
014
VIN[19:0]
AIN1/2
AIN3/4
AIN5/6
AIN7/8
CASCADE
GS1503
BIT
4-0
7-0
4-0
7-0
BIT
7
VOUT[19:0]
SETTING
SETTING
-
-
1
DEFAULT
Y/C b /C r [19:0]
DEFAULT
569d
7d
15879 - 4
0