16
MS0103-E-00
MS0546-E-00
SAHI KASEI [AK5371
]
2007
02
3.2 Class-specific Audio Control Interface
3.3 Class-specific Audio Control Interface Header Descriptor
3.3.1 Contains general information about the audio device.
Offset Field Size Value Description
0 bLength 1 0x09 Size of this descriptor
1 bDescriptorType 1 0x24 CS_INTERFACE
2 bDescriptorSubtype 1 0x01 HEADER subtype
3 bcdADC 2 0x0100 Revision of class specification – 1.0
5 wTotalLength 2 0x0028 Total size of class-specific Audio Control
Interface descriptors (includes this
descriptor)
7 bInCollection 1 0x01 Number of streaming interfaces
8 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 Description
0 bLength 1 0x09 Size of this descriptor
1 bDescriptorType 1 0x24 CS_INTERFACE
2 bDescriptorSubtype 1 0x03 OUTPUT_TERMINAL subtype
3 bTerminalID 1 0x02 ID of this terminal
4 wTerminalType 2 0x0101 USB Streamer
6 bAssocTerminal 1 0x01 ID of associate Input Terminal is 0x01
7 bSourceID 1 0x03 From Feature Unit
8 iTerminal 1 0x00 Unused
3.3.4 Feature Unit descriptor
Offset Field Size Value Description
0 bLength 1 0x0A Size of this descriptor
1 bDescriptorType 1 0x24 CS_INTERFACE
2 bDescriptorSubtype 1 0x06 FEATURE_UNIT descriptor subtype
3 bUnitID 1 0x03 ID of this feature Unit
4 bSourceID 1 0x01 ID to Terminal to which this is connected.
5 bControlSize 1 0x01 Size in bytes of an element of the
bmaControl()
6 bmaControls(0) 1 0x01 D0(Mute) is enable for Channel 0
7 bmaControls(1) 1 0x02 D1(Volume) is enable for ch 1(Left)
8 bmaControls(2) 1 0x02 D1(Volume) is enable for ch 2 (Right)
9 iFeature 1 0x00 Unused
Note that there is never endpoint descriptor for endpoint 0.