AK5371A Datasheet, PDF (16/32 Pages) Asahi Kasei Microsystems – 2ch A/D Converter with USB I/F

ASAHI KASEI
[AK5371A]
3.2 Class-specific Audio Control Interface
3.3 Class-specific Audio Control Interface Header Descriptor
3.3.1
Offset
0
1
2
3
5
7
8
Contains general information about the audio device.
Field
Size Value
Description
bLength
1 0x09
Size of this descriptor
bDescriptorType
1 0x24
CS_INTERFACE
bDescriptorSubtype 1 0x01
HEADER subtype
bcdADC
2 0x0100
Revision of class specification – 1.0
wTotalLength
2 0x0028
Total size of class-specific Audio Control
Interface descriptors (includes this
descriptor)
bInCollection
1 0x01
Number of streaming interfaces
baInterfaceNr(1)
1 0x01
Streaming interface number 1 belongs to
this audio control interface.
3.3.2 Input terminal descriptor
This descriptor describes the signal coming through the input port NumChannels is 1(monaural) and
ChannelConfig is set no position. Terminal type is Microphone.
Offset Field
Size Value
Description
0
bLength
1 0x0C
Size of this descriptor
1
bDescriptorType
1 0x24
CS_INTERFACE
2
bDescriptorSubtype 1 0x02
INPUT_TERMINAL subtype
3
bTerminalID
1 0x01
ID of this terminal
4
wTerminalType
2 0x0201
Terminal is Microphone
6
bAssocTerminal
1 0x02
ID of associated Output Terminal is 0x02
7
bNrChannels
1 0x02
Two channels (Stereo)
8
wChannelConfig
2 0x0003
Left/Right Front
10 iChannelNames
1 0x00
Unused
11 iTerminal
1 0x00
Unused
3.3.3 Output terminal descriptor
This descriptor describes the USB stream to host.
Offset Field
Size Value
0
bLength
1 0x09
1
bDescriptorType
1 0x24
2
bDescriptorSubtype 1 0x03
3
bTerminalID
1 0x02
4
wTerminalType
2 0x0101
6
bAssocTerminal
1 0x01
7
bSourceID
1 0x03
8
iTerminal
1 0x00
Description
Size of this descriptor
CS_INTERFACE
OUTPUT_TERMINAL subtype
ID of this terminal
USB Streamer
ID of associate Input Terminal is 0x01
From Feature Unit
Unused
3.3.4 Feature Unit descriptor
Offset
0
1
2
3
4
5
6
7
8
9
Field
Size Value
Description
bLength
1 0x0A
Size of this descriptor
bDescriptorType
1 0x24
CS_INTERFACE
bDescriptorSubtype 1 0x06
FEATURE_UNIT descriptor subtype
bUnitID
1 0x03
ID of this feature Unit
bSourceID
1 0x01
ID to Terminal to which this is connected.
bControlSize
1 0x01
Size in bytes of an element of the
bmaControl()
bmaControls(0)
1 0x01
D0(Mute) is enable for Channel 0
bmaControls(1)
1 0x02
D1(Volume) is enable for ch 1(Left)
bmaControls(2)
1 0x02
D1(Volume) is enable for ch 2 (Right)
iFeature
1 0x00
Unused
Note that there is never endpoint descriptor for endpoint 0.
MS0546-E-00
MS0103-E-00
16
2007/02