AK4571 Datasheet, PDF (35/54 Pages) Asahi Kasei Microsystems – USB I/F Audio CODEC

ASAHI KASEI
[AK4571]
3.5.4. Type I format type descriptor<Alternate Setting 1>
Offset Field
Size Value
Description
0 blength
1 0x1D
Size of this descriptor
1 bDescriptorType
1 0x24
CS_INTERFACE
2 bDescriptorSubtype 1 0x02
FORMAT_TYPE
3 bFormatType
1 0x01
FORMAT_TYPE_I
4 bNrChannels
1 0x02
Two channels
5 bSubFrameSize
1 0x02
Two bytes per slot
6 bBitResolution
1 0x10
16 bits
7 bSamFreqType
1 0x07
Seven frequencies
8 tSamFreq[0]
3 0x001F40
8000Hz
11 tSamFreq[1]
3 0x002B11
11025Hz
14 tSamFreq[2]
3 0x003E80
16000 Hz
17 tSamFreq[3]
3 0x005622
22050Hz
20 tSamFreq[4]
3 0x007D00
32000 Hz
23 tSamFreq[5]
3 0x00AC44
44100Hz
23 tSamFreq[6]
3 0x00BB80
48000Hz
3.5.5. Endpoint descriptor
Offset Field
Size
0 bLength
1
1 bDescriptorType
1
2 bEndpointAddress
1
3 bmAttributes
1
4 wMaxPacketSize
2
6 bInterval
1
7 bRefresh
1
8 bSynchAddress
1
Value
0x0 9
0x05
0x0 2
0x0 9
0x00C8
0x01
0x00
0x00
Description
Length of this descriptor
ENDPOINT descriptor
Endpoint 2, OUT direction
Adaptive Isochronous,
2byte*(48+2)sample*2ch=200 byte/frame
1millisecond (Must be set to 1)
Unused
Unused
3.5.6.
Class-specific isochronous audio data endpoint descriptor
Offset Field
Size Value
Description
0 bLength
1 0x07
Size of this descriptor
1 bDescriptorType
1 0x25
CS_ENDPOINT
2 bDescriptorSubtype 1 0x01
EP_GEN ERAL
3 bmAttributes
1 0x01
Sample rate control
4 bLockDelayUnits
1 0x00
Unused
5 wLockDelay
2 0x0000
Unused
MS0153-J-02
- 35 -
2003/3