AK5374 Datasheet, PDF (30/51 Pages) Asahi Kasei Microsystems – 24-bit Stereo ADC with USB Interface

4.2.3 Type I Format Type Descriptor
Offset
0
1
2
3
4
5
6
7
8
11
Field
bLength
bDescriptorType
bDescriptorSubtype
bFormatType
bNrChannels
bSubFrameSize
bBitResolution
bSamFreqType
tSamFreq[0]
tSamFreq[1]
Size Value
1 0x0E
1 0x24
1 0x02
1 0x01
1 0x01
1 0x01
1 0x08
1 0x02
3 0x001F40
3 0x003E80
Description
Size of this descriptor in bytes
CS_INTERFACE
FORMAT_TYPE
FORMAT_TYPE_I
One channel
One byte per slot
8 bits
Two frequencies
8000Hz
16000Hz
4.2.4 Standard Endpoint Descriptor
Offset
0
1
2
3
4
6
7
8
Field
bLength
bDescriptorType
bEndpointAddress
bmAttributes
wMaxPacketSize
bInterval
bRefresh
bSynchAddress
Size Value
1 0x09
1 0x05
1 0x81
1 0x0D
2 0x0010
1 0x01
1 0x00
1 0x00
Description
Size of this descriptor in bytes
ENDPOINT descriptor
Endpoint 1, IN direction
Isochronous, synchronous, not shared
1byte*16sample*1ch=16 byte/frame
One packet every frame (Must be set to 1)
4.2.5 Class-specific Isochronous Audio Data Endpoint Descriptor
Offset
0
1
2
3
4
5
Field
bLength
bDescriptorType
bDescriptorSubtype
bmAttributes
bLockDelayUnits
wLockDelay
Size Value
1 0x07
1 0x25
1 0x01
1 0x01
1 0x00
2 0x0000
Description
Size of this descriptor in bytes
CS_ENDPOINT
GENERAL
Sample rate control
Unused
4.3 Operational Alternate Setting 2
4.3.1 Standard Audio Streaming Interface Descriptor (Alt = 2: Mono, 16bit, 48k)
Offset
0
1
2
3
4
5
6
7
8
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size Value
1 0x09
1 0x04
1 0x01
1 0x02
1 0x01
1 0x01
1 0x02
1 0x00
1 0x00
Description
Size of this descriptor in bytes
INTERFACE descriptor
Index of this interface
Index of this setting
Endpoint 1
AUDIO
AUDIO_STREAMING
Not used. Must be set to 0.
Null string
[AK5374]
MS1197-E-00
- 30 -
2010/05