alc272 Realtek Semiconductor Corporation, alc272 Datasheet - Page 20

• Manufacturer Part Number: alc272
• Description: 4 Channel High Definition Audio Codec
• Manufacturer: Realtek Semiconductor Corporation

7.2. Frame Composition
7.2.1.
An outbound frame is composed of one 32-bit command stream and multiple data streams. There are one
or multiple sample blocks in a data stream. Only one sample block exists in a stream if the HDA
controller delivers a 48kHz rate of samples to the codec. Multiple sample blocks in a stream means the
sample rate is a multiple of 48kHz. This means there should be 2 blocks in the same stream to carry
96kHz samples (Figure 6).
For outbound frames, the stream tag is not in SDO, but in the SYNC signal. A new data stream is started
at the end of the stream tag. The stream tag includes a 4-bit preamble and 4-bit stream ID (Figure 7).
To keep the cadence of converters bound to the same stream, samples for these converters must be placed
in the same block.
4 Channel High Definition Audio Codec
SYNC
Previous Frame
SDO
Frame SYNC
Sample 1
Outbound Frame – Single SDO
Block 1
Command Stream
Sample Block(s)
msb
A 48kHz Frame is composed of Command stream and multiple Data streams
Sample 2
Block 2
SYNC
BCLK
SDO
...
lsb
Figure 7.
..
..
.
.
msb first in a sample
Previous Stream
Stream 'A' Data
Figure 6.
Stream 'A' Tag
(Here 'A' = 5)
One or multiple blocks in a stream
Preamble Stream=10
Sample Z
Block Y
(4-Bit)
SDO Stream Tag is Indicated in SYNC
7 6 5 4
Stream Tag
msb
1
For 96kHz rate, Block1 includes (N)
includes (N+1)
3
For 48kHz rate, only Block1 is included
SDO Outbound Frame
Z channels of PCM sample
(4-Bit)
0
2
lsb
1 0
1
12
0
Data of Stream 10
th
time of samples
Stream 'X' Tag
(Here 'X' = 6)
Stream 'X' Data
Null Field
Track ID: JATR-1076-21
th
time of samples, Block2
0s
Padded at the
end of Frame
Next Frame
Datasheet
ALC272
Rev. 1.0