CM6571 Datasheet, PDF (27/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

CM6571
USB Audio Sound Chip
class-specific as type format descriptor (interface 2, alternate 1)
Offset
Field
Size Value (Hex)
Description
0
bLength
1
1D
Descriptor length
1
bDescriptorType
1
24
CS_INTERFACE descriptor type
2
bDescriptorSubtype 1
02
Format descriptor subtype
3
bFormatType
1
01
Format type 1
4
bNrChannels
1
02
Number of channelAlways 2ch
5
bSubframeSize
1
02
2 bytes per slot
6
bBitResolution
1
10
Bit resolution: 16-bits
7
bSamFreqType
1
07
7 sampling rates
8
tSampFreq(1)
3
001F40 Sampling rate: 8kHz
11
tSampFreq(2)
3
002B11 Sampling rate: 11.025kHz
14
tSampFreq(3)
3
003E80 Sampling rate: 16kHz
17
tSampFreq(4)
3
005622 Sampling rate: 22.05kHz
20
tSampFreq(5)
3
007D00 Sampling rate: 32kHz
23
tSampFreq(6)
3
00AC44 Sampling rate: 44.1kHz
26
tSampFreq(7)
3
00BB80 Sampling rate: 48kHz
standard as ISO in audio data endpoint descriptor (ep 82)
Offset
Field
Size Value (Hex)
Description
0
bLength
1
09
Descriptor length
1
bDescriptorType
1
05
Endpoint Descriptor
2
bEndpointAddress 1
82
IN Endpoint, Endpoint number 2
3
bmAttributes
1
0D
ISO Endpoint, synchronous
4
wMaxPacketSize
2
0188 Maximum packet size: 392 bytes
6
bInterval
1
01
1ms
7
bRefresh
1
00
Reset to 0
8
bSynchAddress
1
00
No synchronization pipe
class-specific as ISO in audio data endpoint descriptor (ep 82)
Offset
Field
Size Value (Hex)
Description
0
bLength
1
07
Descriptor length
1
bDescriptorType
1
25
CS_ENDPOINT descriptor type
2
bDescriptorSubtype 1
01
EP_GENERAL descriptor subtype
3
bmAttributes
1
01
Sampling Frequency control
4
bLockDelayUnits
1
00
Reset to 0
5
wLockDelay
2
0000 No synchronization pipe
standard hid interface descriptor (interface 3, alternate 0)
Offset
Field
Size Value (Hex)
Description
0
bLength
1
09
Descriptor length
1
bDescriptorType
1
04
Interface Descriptor
2
bInterfaceNumber 1
03
Interface number: 03
3
bAlternateSetting 1
00
Alternate interface
4
bNumEndpoints
1
01
Number of endpoint used by this interface
5
bInterfaceClass
1
03
Audio Interface Class
6
bInterfaceSubClass 1
00
Subclass code
7
bInterfaceProtocol 1
00
Protocol code
8
iInterface
1
00
Index of string descriptor describing this interface
Revised: Nov. 2012
Page 27 / 63
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