alc880 Realtek Semiconductor Corporation, alc880 Datasheet - Page 22

• Manufacturer Part Number: alc880
• Description: 7.1 Channel High Definition Audio Codec
• Manufacturer: Realtek Semiconductor Corporation

7.2.2.
The HDA controller allows two SDO signals to be used to strip outbound data, completing transmission
in less time to get more bandwidth. If software determines that the target codec supports multiple SDO
capability, it enables the ‘Strip Control’ bit in the controller’s Output Stream Control Register to initiate a
specific stream (Stream ‘A’ in Figure 9) to be transmitted on multiple SDOs. In this case, the MSB of
stream data is always carried on SDO0, the second bit on SDO1 and so forth.
SDO1 is for transmitting a stripped stream. The codec doesn’t support multiple SDOs connected to
SDO0.
To guarantee all codecs can determine their corresponding stream, the command stream is not stripped. It
is always transmitted on SDO0, and copied on SDO1.
7.1 Channel High Definition Audio Codec
SDO
SDO
SYNC
1
0
Frame SYNC
Command stream is unchanged, not stripped
Outbound Frame – Multiple SDOs
Command Stream
Command Stream
Stream 'A' Tag
Stream 'A' to Codec A
D
D
n-1
n
Figure 9.
D
D
n-3
n-2
. .
.
Stream A is "bit-stripped" on SDO0 and SDO1
. .
. .
.
.
Stripped Stream on Multiple SDO
Stream 'X' Tag
12
Stream 'X' to Codec X
0s
Track ID: JATR-1076-21
Stream 'Y' Tag
Stream 'Y' to Codec Y
ALC880 Series
0s
Datasheet
Rev. 1.4