gs9023-cfy ETC-unknow, gs9023-cfy Datasheet - Page 13

• Manufacturer Part Number: gs9023-cfy
• Description: Embedded Audio Codec
• Manufacturer: ETC-unknow

To select 24 bit audio operation, the user must set the
AUXEN pin or the “A4ON” bit of Host Interface Register #1h
HIGH. When the AUXEN pin or “A4ON” bit is HIGH, the
GS9023 does not multiplex the audio data packet and the
associated extended audio data packet if there is
insufficient room for both in the HANC space. In this case,
the “ADERR” bit of Host Interface Register #7h is set HIGH,
indicating an audio packet multiplexing error. The error bit is
cleared when accessed by the Host Interface. The audio
group (Extended packet data ID) for each device is
configured in “AD4ID[3:0]” of Host Interface Register #3h.
On power up, audio group 1 is selected by default.
By cascading four GS9023 devices, it is possible to
multiplex up to 16 audio channels (according to SMPTE
272) in a component video signal as shown in Figure 18.
NOTE: In the 525/D1 video format, only 15 channels of 24
bit audio can be multiplexed in the cascade configuration.
The extended audio data packet structure as described in
SMPTE 272M is shown in Figure 7.
The extended audio data packets words are defined as
follows:
ADF: Ancillary Data Flag. The ancillary data flag marks the
beginning of an ancillary packet and is automatically
generated by the GS9023.
DID: Data ID. Extended audio data packets corresponding
to an audio group are selected by programming “A4ID[3:0]”
of Host Interface Register #3h for audio groups 1 to 4 as
follows:
Group 1: Eh (1FEh)
Group 2: Ch (2FCh)
Group 3: Ah (2FAh)
Group 4: 8h (1F8h)
NOTE: The six most significant bits of the DID are
automatically generated by the GS9023.
DBN: Data Block Number. The data block number is used
when data blocks within a common data ID are to be linked
or to distinguish consecutive data blocks within a common
data ID. The data block number continuously increments
from 1 to 255 and is generated automatically by the
GS9023.
GENNUM CORPORATION
* The ancillary data flag, ADF, is one word in composite systems (ANSI/SMPTE 259M)
and three words in component systems (ANSI/SMPTE 125M).
Fig. 7: Extended Audio Data Packet Structure
13
DC: Data Count. The data count represents the number of
user data words to follow (maximum of 255 words). The
data count is automatically generated by the GS9023.
DATA WORDS: The extended audio data samples are
mapped into ancillary data words as shown in Table 5.
TABLE 5: Extended Audio Packet Data Sample Structure
The extended audio packet data sample bits are defined as
follows:
x[3:0]: Auxiliary data from subframe 1.
y[3:0]: Auxiliary data from subframe 2.
a: Address pointer. LOW for channels 1 and 2, and HIGH for
channels 3 and 4. This bit is internally generated by the
GS9023.
CS: Checksum. The checksum consists of nine bits. The
checksum is used to determine the validity of the words
data ID through user data. It is the sum of the nine least
significant bits of the words data ID through user data. The
checksum is automatically generated by the GS9023.
Audio Control Packets
The audio control packet structure is detailed in SMPTE
272M. The audio group (Audio control packet data ID) for
each device is configured in “ACID[3:0]” of Host Interface
Register #4h. The Audio control parameters are configured
in Host Interface Registers #Ah, #Bh, #Ch and #Dh. The
audio control packet multiplexing positions for the various
BIT
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
ANC DATA WORD
y3 (MSB)
x3 (MSB)
y0 (LSB)
x0 (LSB)
not b8
y2
y1
x2
x1
a
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