CM6571 Datasheet, PDF (21/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

CM6571
USB Audio Sound Chip
8 USB function description
8.1 USB audio topology
The MCU of CM6571 can use internal ROM code or download customized code to implement USB audio device in
different topologies. This USB device can provide one control pipe, two ISO IN/OUT pipes, one interrupt pipe and four
BULK IN/OUT pipes.
8.2 Example topology –headset
0x01
IT
USB STREAM
0x07
FEA
0x09
MIXER
0x05
FEA
0x03
OT
SPEAKER
0x02
IT
MIC
0x06
FEA
0x08
SEL
0x04
OT
USB STREAM
device descriptor
Offset
Field
Size Value (Hex)
Description
0
bLength
1
12
Descriptor length
1
bDescriptorType
1
01
Device Descriptor
2
bcdUSB
2
0110 USB 1.1 compliant
4
bDeviceClass
1
00
Device class specified by interface
5
bDeviceSubClass
1
00
Device subclass specified by interface
6
bDeviceProtocol
1
00
Device protocol specified by interface
7
bMaxPacketSize0
1
10
Endpoint zero packet size
8
idVendor
2
0D8C Vendor ID
10
idProduct
2 0178~017F Product ID
12
bcdDevice
2
0000 Device release number
14
iManufacturer
1
01
Index of string descriptor describing manufacturer
15
iProduct
1
02
Index of string descriptor describing product
16
iSerialNumber
1
00
Index of string descriptor describing serial number
17
bNumConfigurations 1
01
Number of configuration
Revised: Nov. 2012
Page 21 / 63
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