CM6533-N Datasheet, PDF (31/60 Pages) C-Media Electronics – USB 2.0 Full-Speed compliant

CM6533,CM6533N,CM6533X1,CM6533DH
USB Audio Chip
Marks a word containing data for channel A (left) at the start of the data-block.
Preamble “M”:
Marks a word with data for channel A that is not at the start of the data-block.
Preamble “W”:
Marks a word containing data for channel B (right, for stereo). When using more than 2 channels, this could also be
any other channel (except for A).
The number of subframes that are used depends on the number of channels that is transmitted. A CD-player uses
Channels A and B (left/right) and so each frame contains two subframes. A block contains 192 frames and starts with
a preamble "B":
Sub-frame
0
34
78
Preamble Aux Data
LSB
Audio Data
27 28 29 30 31
MSB
VUCP
V: Valid, U:User-Data, C:Channel-Status-Data, P:Parity-Bit
Figure -1 SPDIF Subframe Description
In each block, 384 bits of channel status and subcode info are transmitted. The Channel-status bits are equal for both
subframes, so actually only 192 useful bits are transmitted:
M ChannelA W ChannelA B ChannelA W ChannelA M ChannelA W ChannelA
SubFrame SubFrame
Frame 191
Frame 0
Frame 1
Figure -2 Preamble Description of 192 SPDIF frame
6.6.2 SPDIF Out Channel Status
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
byte0
consumer
/professional
audio/
non-audio
copyright
pre-emphasis
mode
default
byte1
default
byte2
default
byte3
default
0(P)
0(P)
0(fixed)
0(P)
0(P)
1(P)
0(P)
category code
0(P)
0(P)
0(P)
source number
0(fixed) 0(fixed) 0(fixed)
sampling frequency
0(P)
0(P)
0(P)
0(fixed) 0(fixed) 0(fixed) 0(fixed)
L
0(P)
0(P)
0(P)
0(P)
channel number
0(fixed) 0(fixed) 0(fixed) 0(fixed)
clock accuracy
reserved
0(fixed) 0(fixed) 0(fixed) 0(fixed)
**Note: (P) These bits can be programmed by USB HID or USB vendor command
Page 31 / 60
Rev.1.6
www.cmedia.com.tw
Copyright© C-Media Electronics Inc.