With the help from this website:
http://forum.xda-developers.com/showthread.php?t=1852343
The USB configuration of Nexus 7, after claiming the USB accessory and USB Audio, is shown below. The tools used is lsusb.
I think there is bugs:
(1) Line 73 to 75, I think it should be:
73 bInCollection 1
74 baInterfaceNr( 0) 2
The Audio streaming interface has number 2, should I think line 74 should be 2.
2) Line 132, I think it should be:
bTerminalLink 3
It should be 3 instead of 1, to match the terminal ID on line 93.
Can someone tell me if this is correct?
<![CDATA[
1 Bus 001 Device 005: ID 18d1:2d05 Google Inc.
2 Device Descriptor:
3 bLength 18
4 bDescriptorType 1
5 bcdUSB 2.00
6 bDeviceClass 0 (Defined at Interface level)
7 bDeviceSubClass 0
8 bDeviceProtocol 0
9 bMaxPacketSize0 64
10 idVendor 0x18d1 Google Inc.
11 idProduct 0x2d05
12 bcdDevice 99.99
13 iManufacturer 2 asus
14 iProduct 3 Nexus
15 iSerial 4 015d188495400a11
16 bNumConfigurations 1
17 Configuration Descriptor:
18 bLength 9
19 bDescriptorType 2
20 wTotalLength 156
21 bNumInterfaces 4
22 bConfigurationValue 1
23 iConfiguration 0
24 bmAttributes 0x80
25 (Bus Powered)
26 MaxPower 500mA
27 Interface Descriptor:
28 bLength 9
29 bDescriptorType 4
30 bInterfaceNumber 0
31 bAlternateSetting 0
32 bNumEndpoints 2
33 bInterfaceClass 255 Vendor Specific Class
34 bInterfaceSubClass 255 Vendor Specific Subclass
35 bInterfaceProtocol 0
36 iInterface 6 Android Accessory Interface
37 Endpoint Descriptor:
38 bLength 7
39 bDescriptorType 5
40 bEndpointAddress 0x81 EP 1 IN
41 bmAttributes 2
42 Transfer Type Bulk
43 Synch Type None
44 Usage Type Data
45 wMaxPacketSize 0x0200 1x 512 bytes
46 bInterval 0
47 Endpoint Descriptor:
48 bLength 7
49 bDescriptorType 5
50 bEndpointAddress 0x02 EP 2 OUT
51 bmAttributes 2
52 Transfer Type Bulk
53 Synch Type None
54 Usage Type Data
55 wMaxPacketSize 0x0200 1x 512 bytes
56 bInterval 0
57 Interface Descriptor:
58 bLength 9
59 bDescriptorType 4
60 bInterfaceNumber 1
61 bAlternateSetting 0
62 bNumEndpoints 0
63 bInterfaceClass 1 Audio
64 bInterfaceSubClass 1 Control Device
65 bInterfaceProtocol 0
66 iInterface 0
67 AudioControl Interface Descriptor:
68 bLength 10
69 bDescriptorType 36
70 bDescriptorSubtype 1 (HEADER)
71 bcdADC 1.00
72 wTotalLength 40
73 bInCollection 2
74 baInterfaceNr( 0) 0
75 baInterfaceNr( 1) 1
76 AudioControl Interface Descriptor:
77 bLength 12
78 bDescriptorType 36
79 bDescriptorSubtype 2 (INPUT_TERMINAL)
80 bTerminalID 1
81 wTerminalType 0x0201 Microphone
82 bAssocTerminal 0
83 bNrChannels 2
84 wChannelConfig 0x0003
85 Left Front (L)
86 Right Front (R)
87 iChannelNames 0
88 iTerminal 0
89 AudioControl Interface Descriptor:
90 bLength 9
91 bDescriptorType 36
92 bDescriptorSubtype 3 (OUTPUT_TERMINAL)
93 bTerminalID 3
94 wTerminalType 0x0101 USB Streaming
95 bAssocTerminal 2
96 bSourceID 2
97 iTerminal 0
98 AudioControl Interface Descriptor:
99 bLength 9
100 bDescriptorType 36
101 bDescriptorSubtype 6 (FEATURE_UNIT)
102 bUnitID 2
103 bSourceID 1
104 bControlSize 2
105 bmaControls( 0) 0x00
106 bmaControls( 0) 0x00
107 iFeature 0
108 Interface Descriptor:
109 bLength 9
110 bDescriptorType 4
111 bInterfaceNumber 2
112 bAlternateSetting 0
113 bNumEndpoints 0
114 bInterfaceClass 1 Audio
115 bInterfaceSubClass 2 Streaming
116 bInterfaceProtocol 0
117 iInterface 0
118 Interface Descriptor:
119 bLength 9
120 bDescriptorType 4
121 bInterfaceNumber 2
122 bAlternateSetting 1
123 bNumEndpoints 1
124 bInterfaceClass 1 Audio
125 bInterfaceSubClass 2 Streaming
126 bInterfaceProtocol 0
127 iInterface 0
128 AudioStreaming Interface Descriptor:
129 bLength 7
130 bDescriptorType 36
131 bDescriptorSubtype 1 (AS_GENERAL)
132 bTerminalLink 1
133 bDelay 1 frames
134 wFormatTag 1 PCM
135 AudioStreaming Interface Descriptor:
136 bLength 11
137 bDescriptorType 36
138 bDescriptorSubtype 2 (FORMAT_TYPE)
139 bFormatType 1 (FORMAT_TYPE_I)
140 bNrChannels 2
141 bSubframeSize 2
142 bBitResolution 16
143 bSamFreqType 1 Discrete
144 tSamFreq[ 0] 44100
145 Endpoint Descriptor:
146 bLength 9
147 bDescriptorType 5
148 bEndpointAddress 0x83 EP 3 IN
149 bmAttributes 13
150 Transfer Type Isochronous
151 Synch Type Synchronous
152 Usage Type Data
153 wMaxPacketSize 0x0100 1x 256 bytes
154 bInterval 4
155 bRefresh 0
156 bSynchAddress 0
157 AudioControl Endpoint Descriptor:
158 bLength 7
159 bDescriptorType 37
160 bDescriptorSubtype 1 (EP_GENERAL)
161 bmAttributes 0x01
162 Sampling Frequency
163 bLockDelayUnits 1 Milliseconds
164 wLockDelay 1 Milliseconds
165 Interface Descriptor:
166 bLength 9
167 bDescriptorType 4
168 bInterfaceNumber 3
169 bAlternateSetting 0
170 bNumEndpoints 2
171 bInterfaceClass 255 Vendor Specific Class
172 bInterfaceSubClass 66
173 bInterfaceProtocol 1
174 iInterface 0
175 Endpoint Descriptor:
176 bLength 7
177 bDescriptorType 5
178 bEndpointAddress 0x82 EP 2 IN
179 bmAttributes 2
180 Transfer Type Bulk
181 Synch Type None
182 Usage Type Data
183 wMaxPacketSize 0x0200 1x 512 bytes
184 bInterval 0
185 Endpoint Descriptor:
186 bLength 7
187 bDescriptorType 5
188 bEndpointAddress 0x03 EP 3 OUT
189 bmAttributes 2
190 Transfer Type Bulk
191 Synch Type None
192 Usage Type Data
193 wMaxPacketSize 0x0200 1x 512 bytes
194 bInterval 0
195 Device Qualifier (for other device speed):
196 bLength 10
197 bDescriptorType 6
198 bcdUSB 2.00
199 bDeviceClass 0 (Defined at Interface level)
200 bDeviceSubClass 0
201 bDeviceProtocol 0
202 bMaxPacketSize0 64
203 bNumConfigurations 1
204 Device Status: 0x0000
205 (Bus Powered)
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