UAC的规格书可以从usb.org网站下载,目前有1.0,2.0,3.0三个版本,本文以1.0为例分享一个UAC扬声器的实例, 重点在于描述符拓扑。
规格书《UAC1.0/USB_AV_Specification_Rev_1.0》定义了UAC设备类完整的信息，但是比较复杂,《UAC1.0\BasicAudioDevice-10\BasicAudioDevice-10.pdf》定义了其一个最小子集，一般我们实现其子集就够了。所以我们可以参考BasicAudioDevice-10.pdf的最简拓扑结构实现设备，然后具体的描述符，请求等细节可以参考USB_AV_Specification_Rev_1.0。
BasicAudioDevice-10.pdf定义了需要支持的3个设备
Headphone:耳机设备,实际上声音播放的都算,所以PC上叫扬声器或者耳机。
Microphone:麦克风设备。
Headset:以上两者的集合,既有麦克风又有扬声器。
我们接下来就分三篇分享下这个三个设备实例，包括描述符拓扑,枚举过程等。
前面已经分享了扬声器和麦克风设备，本文继续分享扬声器+麦克风实例。
我们这里以最简单的单声道为例。
如下是其拓扑结构，本示例拓扑包括特征单元7和混音单元8，可以不要，即可以简化为如下
麦克风: mic采集 -> 输入终端4 -> 特征单元5 -> 输出终端6- > USB IN端点。
扬声器:USB OUT端点 -> 输入终端1->特征单元2->输出终端3 -> 喇叭输出。
即前面介绍的扬声器和麦克风的组合。
其中特征单元用于静音，音量控制等。
相关描述符参考BasicAudioDevice-10.pdf的第七章
我这里分享一个基于IAD的描述符拓扑实例
一共3个接口,接口2是控制接口，接口3是扬声器流，接口4是麦克风流。
接口3的alt0是0带宽接口，设置接口选择该alt时关闭扬声器流，alt1是数据流接口，设置接口选择该alt时启动扬声器流，该接口下有一个OUT端点用于接收数据。
接口4的alt0是0带宽接口，设置接口选择该alt时关闭麦克风流，alt1是数据流接口，设置接口选择该alt时启动麦克风流，该接口下有一个IN端点用于发送数据。
控制接口中包括
扬声器的:输入终端1，特征单元2和输出终端3。流接口3的alt 1绑定到输入终端，
而输入终端对应的是OUT端点0x02
麦克风的:输入终端4，特征单元5和输出终端6。流接口4的alt 1绑定到输出终端，
而输出终端对应的是IN端点0x82，注意这里在特征单元5和输出终端6之间插入了选择单元9.
设备描述符和配置描述符如下，字符串描述符就略去了，描述符后有详细的注释和注意说明，不再赘述。
static const uint8_t dev_desc[] ={0x12, /* bLength 本描述符长度,固定为0x12 */0x01, /* bDescriptorType 描述符类型DEVICE=1, 见Table 9-5. Descriptor Types */0x00,0x02, /* bcdUSB USB规格书发布编号,BCD,小端 *//* bDeviceClass-bDeviceSubClass-DeviceProtocol决定具体设备类型 见https://www.usb.org/defined-class-codes* 这里EF-02-01表示IAD设备*/0xEF, /* bDeviceClass 设备类类型 */0x02, /* bDeviceSubClass 设备子类 */0x01, /* bDeviceProtocol 设备协议 */0x40, /* bMaxPacketSize0 控制端点最大包大小 */0x4A,0x4C, /* idVendor 厂商ID VID,小端*/0x55,0x4C, /* idProduct 产品ID PID,小端*/0x00,0x01, /* bcdDevice 设备发布号,BCD,小端*/0x01, /* iManufacturer 制造商字符串描述符索引 */0x02, /* iProduct 产品字符串描述符索引 */0x03, /* iSerialNumber 设备序列号字符串描述符索引 0则不使用 */0x01, /* bNumConfigurations 配置个数 */};static const uint8_t cfg_desc[] = {/* 配置描述符见Table 9-10. Standard Configuration Descriptor */0x09, /* bLength 本描述符长度,固定为9 */0x02, /* bDescriptorType 描述符类型CONFIGURATION =0x02, 见Table 9-5. Descriptor Types P251 */0xCF, /* wTotalLength 本配置符所有内容长度,小端 */0x00,0x03, /* bNumInterfaces 本配置的接口数 一个控制一个流 */0x01, /* bConfigurationValue 设置配置请求,选择该配置的对应的设置值 */0x00, /* iConfiguration 本配置对应的字符串描述符,配置为0则没有 */0x80, /* bmAttributes 配置特征 D7固定为1 D6:Self-powered D5:Remote Wakeup*/0xC8, /* bMaxPower 最大消耗电流,单位2mA *//********************************************************* 以下是MIC+SPK部分*******************************************************//*** IAD描述符 参考InterfaceAssociationDescriptor_ecn P4*/0x08, /* bLength 本描述符长度,固定为8 */0x0B, /* bDescriptorType 描述符类型 INTERFACE_ASSOCIATION=0x0B 参考InterfaceAssociationDescriptor_ecn P3 */SPK_AC_ITF, /* bFirstInterface 本IAD下第一个接口 */0x03, /* bInterfaceCount 本IAD下接口数,默认一个控制接口一个SPK流接口一个MIC流接口 */0x01, /* bFunctionClass UAC是接口中说明类功能 这里应该是接口类 见https://www.usb.org/defined-class-codes (Audio=1) 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x02, /* bFunctionSubClass UAC是接口中说明类功能 这里应该是接口类子类 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOSTREAMING=0x02 */0x00, /* bFunctionProtocol UAC是接口中说明类功能 这里应该是接口协议号 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED=0x00 */0x07, /* iFunction 对应字符串索引 *//********************************************************* 控制接口部分*******************************************************//* 接口描述符 UAC是接口描述符说明功能* 见usb_20 P268 Table 9-12. Standard Interface Descriptor*/0x09, /* bLength */0x04, /* bDescriptorType 见usb_20 P251 Table 9-5. Descriptor Types INTERFACE=4 */SPK_AC_ITF, /* bInterfaceNumber */0x00, /* bAlternateSetting */0x00, /* bNumEndpoints 本接口下无端点*/0x01, /* bInterfaceClass (Audio) 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x01, /* bInterfaceSubClass (Audio Control) 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOCONTROL=0x01 */0x00, /* bInterfaceProtocol 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED=0x00 */0x07, /* iInterface 对应字符串索引 *//* BasicAudioDevice-10.pdf P57 Table 7-4: Headset Class-Specific AC Interface Header Descriptor */0x0A, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x01, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes HEADER=0x01 */0x00,0x01, /* bcdADC Audio 1.0 */0x4D,0x00, /* wTotalLength 本接口下后续所有描述符的长度 包括本描述符 */0x02, /* bInCollection 2个流接口 */SPK_AS_ITF, /* baInterfaceNr(1) SPK流接口号 */MIC_AS_ITF, /* baInterfaceNr(2) MIC流接口号 *//* BasicAudioDevice-10.pdf P22 Table 5-3: Mono Input Terminal Descriptor* BasicAudioDevice-10.pdf P21 5.3.3.1.3 Headphone Input Terminal ID1 Descriptor* BasicAudioDevice-10.pdf P58 7.3.3.1.3 Headset Input Terminal ID1 Descriptor*/0x0C, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x02, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes INPUT_TERMINAL=0x02 */SPK_INPUT_TID,/* bTerminalID TID=1*/0x01,0x01, /* wTerminalType TT Headphone Input Terminal */0x00, /* bAssocTerminal */0x01, /* bNrChannels 1个通道 */0x04,0x00, /* wChannelConfig Center Front channel. */0x00, /* iChannelNames 固定为0 */0x00, /* iTerminal 对应字符串描述符索引 *//* BasicAudioDevice-10.pdf P24 Table 5-5: Mono Feature Unit Descriptor* BasicAudioDevice-10.pdf P59 7.3.3.1.7 Headset Feature Unit ID2 Descriptor*/0x09, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x06, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes FEATURE_UNIT=0x06 */SPK_FEATURE_TID, /* bUnitID */SPK_INPUT_TID, /* bSourceID */0x01, /* bControlSize *//**A bit set to 1 indicates that the mentionedControl is supported for master channel0:D0: MuteD1: VolumeD2: BassD3: MidD4: TrebleD5: Graphic EqualizerD6: Automatic GainD7: DelayD8: Bass BoostD9: LoudnessD10..(n*8-1): Reserved*/0x01, /* bmaControls(0) Mute Control on Master Channel.*//*A bit set to 1 indicates that the mentionedControl is supported for logical channel 1 */0x02, /* bmaControls(1) Volume Control on Center Front channel */0x00, /* iFeature 对应字符串描述符索引 *//* BasicAudioDevice-10.pdf P25 Table 5-7: Headphone Output Terminal ID3 Descriptor* BasicAudioDevice-10.pdf P67 7.3.3.1.16 Headset Output Terminal ID3 Descriptor*/0x09, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x03, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes OUTPUT_TERMINAL=0x03 */SPK_OUTPUT_TID, /* bTerminalID */0x02, 0x03, /* 0x0301扬声器 0x0302耳机 Headphones Terminal Type (0x0302) */0x00, /* bAssocTerminal */SPK_FEATURE_TID, /* bSourceID */0x00, /* iTerminal *//* BasicAudioDevice-10.pdf P59 7.3.3.1.6 Headset Microphone Input Terminal ID4 Descriptor* BasicAudioDevice-10.pdf P40 6.3.3.1.3 Microphone Input Terminal ID4 Descriptor* BasicAudioDevice-10.pdf P22 Table 5-3: Mono Input Terminal Descriptor*/0x0C, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x02, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes INPUT_TERMINAL=0x02 */MIC_INPUT_TID,/* bTerminalID TID=4*/0x01,0x02, /* wTerminalType TT Terminal is Microphone. */0x00, /* bAssocTerminal */0x01, /* bNrChannels 1个通道 */0x04,0x00, /* wChannelConfig Center Front channel. @todo 0x0000改为0004*/0x00, /* iChannelNames 固定为0 */0x00, /* iTerminal 对应字符串描述符索引 *//** BasicAudioDevice-10.pdf P60 7.3.3.1.10 Headset Feature Unit ID5 Descriptor*/0x09, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x06, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes FEATURE_UNIT=0x06 */MIC_FEATURE_TID, /* bUnitID */MIC_INPUT_TID, /* bSourceID */0x01, /* bControlSize *//**A bit set to 1 indicates that the mentionedControl is supported for master channel0:D0: MuteD1: VolumeD2: BassD3: MidD4: TrebleD5: Graphic EqualizerD6: Automatic GainD7: DelayD8: Bass BoostD9: LoudnessD10..(n*8-1): Reserved*/0x43, /* bmaControls(0) Mute Control on Master Channel.*//*A bit set to 1 indicates that the mentionedControl is supported for logical channel 1 */0x00, /* bmaControls(1) Volume Control on Center Front channel */0x00, /* iFeature 对应字符串描述符索引 *//* BasicAudioDevice-10.pdf P66 Table 7-12: Headset Selector Unit ID9 Descriptor for HS2 */0x07, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x05, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes SELECTOR_UNIT=0x05 */MIC_SEL_TID, /* bUnitID */0x01, /* bNrInPins */MIC_FEATURE_TID, /* baSourceID(1) */0x00, /* iSelector *//** BasicAudioDevice-10.pdf P67 7.3.3.1.17 Headset Output Terminal ID6 Descriptor*/0x09, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x03, /* bDescriptorSubtype 见audio10.pdf P100 Table A-5: Audio Class-Specific AC Interface Descriptor Subtypes OUTPUT_TERMINAL=0x03 */MIC_OUTPUT_TID, /* bTerminalID */0x01,0x01, /* wTerminalType USB Streaming Terminal Type*/0x02, /* bAssocTerminal */MIC_SEL_TID, /* bSourceID */0x00, /* iTerminal *//********************************************************* SPK流部分*******************************************************//* 接口描述符* usb_20.pdf P268 Table 9-12. Standard Interface Descriptor* BasicAudioDevice-10.pdf P30 Table 5-13: Headphone Standard AS Interface Descriptor (Alt. Set. 0)*/0x09, /* bLength */0x04, /* bDescriptorType INTERFACE */SPK_AS_ITF, /* bInterfaceNumber */0x00, /* bAlternateSetting */0x00, /* bNumEndpoints */0x01, /* bInterfaceClass 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x02, /* bInterfaceSubClass 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOSTREAMING=0x02 */0x00, /* bInterfaceProtocol 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED = 0x00 */0x00, /* iInterface *//* 接口描述符* usb_20.pdf P268 Table 9-12. Standard Interface DescriptorBasicAudioDevice-10.pdf P31 Table 5-14: Headphone Standard AS Interface Descriptor (Alt. Set .1)*/0x09, /* bLength */0x04, /* bDescriptorType INTERFACE */SPK_AS_ITF, /* bInterfaceNumber */0x01, /* bAlternateSetting */0x01, /* bNumEndpoints 一个端点 */0x01, /* bInterfaceClass 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x02, /* bInterfaceSubClass 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOSTREAMING=0x02 */0x00, /* bInterfaceProtocol 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED = 0x00 */0x00, /* iInterface *//** BasicAudioDevice-10.pdf P31 Table 5-15: Headphone Class-specific AS General Interface Descriptor*/0x07, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x01, /* bDescriptorSubtype 见audio10.pdf P100 Table A-6: Audio Class-Specific AS Interface Descriptor Subtypes AS_GENERAL=0x01 */SPK_INPUT_TID, /* bTerminalLink */0x01, /* bDelay Total interface delay, expressed in frames. Not used and shall be set to 0x00 */0x01,0x00, /* wFormatTag PCM Format *//** BasicAudioDevice-10.pdf P32 Table 5-16: Mono Headphone Type I Format Type Descriptor*/0x0B, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x02, /* bDescriptorSubtype 见audio10.pdf P100 Table A-6: Audio Class-Specific AS Interface Descriptor Subtypes FORMAT_TYPE=0x02 */0x01, /* bFormatType 见frmts10.pdf P20 Table A-4: Format Type Codes FORMAT_TYPE_I=0x01 */0x01, /* bNrChannels One channel. */0x02, /* bSubFrameSize Two bytes per audio subframe. */0x10, /* bBitResolution 16 bits per sample */0x01, /* bSamFreqType One frequency supported. */0x80,0x3E,0x00, /* tSamFreq 0x003E80=16000 *//* 端点描述符* usb_20.pdf P269 Table 9-13. Standard Endpoint Descriptor* BasicAudioDevice-10.pdf P33 Table 5-18: Mono Headphone Standard AS Audio Data Endpoint Descriptor*/0x09, /* bLength */0x05, /* bDescriptorType 见usb_20.pdf P251 Table 9-5. Descriptor Types ENDPOINT=5 */SPK_OUT_EP, /* bEndpointAddress */0x0D, /* bmAttributes b[1:0] 01 = Isochronous, b[3:2] 11 = Synchronous */0x20, 0x00, /* wMaxPacketSize */0x01, /* bInterval 1ms一包 */0x00, /* bRefresh */0x00, /* bSynchAddress *//** BasicAudioDevice-10.pdf P33 Table 5-20: Headphone Class-specific Isoc. Audio Data Endpoint Descriptor*/0x07, /* bLength */0x25, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_ENDPOINT=0x25 */0x01, /* bDescriptorSubtype 见audio10.pdf P101 Table A-8: Audio Class-Specific Endpoint Descriptor Subtypes EP_GENERAL=0x01. */0x00, /* bmAttributes No sampling frequency control, no pitch control, no packet padding.*/0x00, /* bLockDelayUnits */0x00, 0x00, /* wLockDelay *//********************************************************* MIC流部分*******************************************************//* 接口描述符* usb_20.pdf P268 Table 9-12. Standard Interface Descriptor* BasicAudioDevice-10.pdf P30 Table 5-13: Headphone Standard AS Interface Descriptor (Alt. Set. 0)*/0x09, /* bLength */0x04, /* bDescriptorType INTERFACE */MIC_AS_ITF, /* bInterfaceNumber */0x00, /* bAlternateSetting */0x00, /* bNumEndpoints */0x01, /* bInterfaceClass 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x02, /* bInterfaceSubClass 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOSTREAMING=0x02 */0x00, /* bInterfaceProtocol 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED = 0x00 */0x00, /* iInterface *//* 接口描述符* usb_20.pdf P268 Table 9-12. Standard Interface DescriptorBasicAudioDevice-10.pdf P31 Table 5-14: Headphone Standard AS Interface Descriptor (Alt. Set .1)*/0x09, /* bLength */0x04, /* bDescriptorType INTERFACE */MIC_AS_ITF, /* bInterfaceNumber */0x01, /* bAlternateSetting */0x01, /* bNumEndpoints 一个端点 */0x01, /* bInterfaceClass 见audio10.pdf P99 Table A-1: Audio Interface Class Code AUDIO=1 */0x02, /* bInterfaceSubClass 见audio10.pdf P99 Table A-2: Audio Interface Subclass Codes AUDIOSTREAMING=0x02 */0x00, /* bInterfaceProtocol 见audio10.pdf P99 Table A-3: Audio Interface Protocol Codes PR_PROTOCOL_UNDEFINED = 0x00 */0x00, /* iInterface *//** BasicAudioDevice-10.pdf P31 Table 5-15: Headphone Class-specific AS General Interface Descriptor*/0x07, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x01, /* bDescriptorSubtype 见audio10.pdf P100 Table A-6: Audio Class-Specific AS Interface Descriptor Subtypes AS_GENERAL=0x01 */MIC_OUTPUT_TID, /* bTerminalLink */0x01, /* bDelay Total interface delay, expressed in frames. Not used and shall be set to 0x00 */0x01,0x00, /* wFormatTag PCM Format *//** BasicAudioDevice-10.pdf P32 Table 5-16: Mono Headphone Type I Format Type Descriptor*/0x0B, /* bLength */0x24, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_INTERFACE=0x24 */0x02, /* bDescriptorSubtype 见audio10.pdf P100 Table A-6: Audio Class-Specific AS Interface Descriptor Subtypes FORMAT_TYPE=0x02 */0x01, /* bFormatType 见frmts10.pdf P20 Table A-4: Format Type Codes FORMAT_TYPE_I=0x01 */0x01, /* bNrChannels One channel. */0x02, /* bSubFrameSize Two bytes per audio subframe. */0x10, /* bBitResolution 16 bits per sample */0x01, /* bSamFreqType One frequency supported. */0x80,0x3E,0x00, /* tSamFreq 0x003E80=16000 *//* 端点描述符* usb_20.pdf P269 Table 9-13. Standard Endpoint Descriptor* BasicAudioDevice-10.pdf P33 Table 5-18: Mono Headphone Standard AS Audio Data Endpoint Descriptor*/0x09, /* bLength */0x05, /* bDescriptorType 见usb_20.pdf P251 Table 9-5. Descriptor Types ENDPOINT=5 */MIC_IN_EP, /* bEndpointAddress */0x0D, /* bmAttributes b[1:0] 01 = Isochronous, b[3:2] 11 = Synchronous */0x20, 0x00, /* wMaxPacketSize */0x01, /* bInterval 1ms一包 */0x00, /* bRefresh */0x00, /* bSynchAddress *//** BasicAudioDevice-10.pdf P33 Table 5-20: Headphone Class-specific Isoc. Audio Data Endpoint Descriptor*/0x07, /* bLength */0x25, /* bDescriptorType 见audio10.pdf P99 Table A-4: Audio Class-specific Descriptor Types CS_ENDPOINT=0x25 */0x01, /* bDescriptorSubtype 见audio10.pdf P101 Table A-8: Audio Class-Specific Endpoint Descriptor Subtypes EP_GENERAL=0x01. */0x00, /* bmAttributes No sampling frequency control, no pitch control, no packet padding.*/0x00, /* bLockDelayUnits */0x00, 0x00, /* wLockDelay */};
如下是UsbTreeView抓到的描述符
Device Descriptor ----------------------bLength : 0x12 (18 bytes)bDescriptorType : 0x01 (Device Descriptor)bcdUSB : 0x200 (USB Version 2.0)bDeviceClass : 0xEF (Miscellaneous)bDeviceSubClass : 0x02bDeviceProtocol : 0x01 (IAD - Interface Association Descriptor)bMaxPacketSize0 : 0x40 (64 bytes)idVendor : 0x4C4A (Unknown Vendor)idProduct : 0x4C55bcdDevice : 0x0100iManufacturer : 0x01 (String Descriptor 1)Language 0x0409 : "xxxxx.Technology"iProduct : 0x02 (String Descriptor 2)Language 0x0409 : "USB.Audio"iSerialNumber : 0x03 (String Descriptor 3)Language 0x0409 : "0.1"bNumConfigurations : 0x01 (1 Configuration)Data (HexDump) : 12 01 00 02 EF 02 01 40 4A 4C 55 4C 00 01 01 02 .......@JLUL....03 01 ..Configuration Descriptor -------------------bLength : 0x09 (9 bytes)bDescriptorType : 0x02 (Configuration Descriptor)wTotalLength : 0x00CF (207 bytes)bNumInterfaces : 0x03 (3 Interfaces)bConfigurationValue : 0x01 (Configuration 1)iConfiguration : 0x00 (No String Descriptor)bmAttributes : 0x80D7: Reserved, set 1 : 0x01D6: Self Powered : 0x00 (no)D5: Remote Wakeup : 0x00 (no): Reserved, set 0 : 0x00MaxPower : 0xC8 (400 mA)Data (HexDump) : 09 02 CF 00 03 01 00 80 C8 08 0B 02 03 01 02 00 ................07 09 04 02 00 00 01 01 00 07 0A 24 01 00 01 4D ...........$...F00 02 03 04 0C 24 02 01 01 01 00 01 04 00 00 00 .....$..........09 24 06 02 01 01 01 02 00 09 24 03 03 02 03 00 .$........$.....02 00 0C 24 02 04 01 02 00 01 04 00 00 00 09 24 ...$...........$06 05 04 01 43 00 00 07 24 05 09 01 05 00 09 24 ....C...$......$03 06 01 01 02 09 00 09 04 03 00 00 01 02 00 00 ................09 04 03 01 01 01 02 00 00 07 24 01 01 01 01 00 ..........$.....0B 24 02 01 01 02 10 01 80 3E 00 09 05 02 0D 20 .$.......>.....00 01 00 00 07 25 01 00 00 00 00 09 04 04 00 00 .....%..........01 02 00 00 09 04 04 01 01 01 02 00 00 07 24 01 ..............$.06 01 01 00 0B 24 02 01 01 02 10 01 80 3E 00 09 .....$.......>..05 82 0D 20 00 04 00 00 07 25 01 00 00 00 00 ... .....%.....IAD Descriptor --------------------bLength : 0x08 (8 bytes)bDescriptorType : 0x0B (Interface Association Descriptor)bFirstInterface : 0x02 (Interface 2)bInterfaceCount : 0x03 (3 Interfaces)The total number of interfaces (3) must be greater than or equal tothe highest linked interface number (base 2 + count 3 = 5)bFunctionClass : 0x01 (Audio)bFunctionSubClass : 0x02 (Audio Streaming)bFunctionProtocol : 0x00iFunction : 0x07 (String Descriptor 7)Language 0x0409 : "USB.Audio"Data (HexDump) : 08 0B 02 03 01 02 00 07 ........Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x02 (Interface 2)bAlternateSetting : 0x00bNumEndpoints : 0x00 (Default Control Pipe only)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x01 (Audio Control)bInterfaceProtocol : 0x00iInterface : 0x07 (String Descriptor 7)Language 0x0409 : "USB.Audio"Data (HexDump) : 09 04 02 00 00 01 01 00 07 .........Audio Control Interface Header Descriptor ------bLength : 0x0A (10 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x01 (Header)bcdADC : 0x0100wTotalLength : 0x004D (77 bytes)bInCollection : 0x02: 0x03: 0x04Data (HexDump) : 0A 24 01 00 01 4D 00 02 03 04 .$...F....Audio Control Input Terminal Descriptor -------bLength : 0x0C (12 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x02 (Input Terminal)bTerminalID : 0x01wTerminalType : 0x0101 (USB Streaming)bAssocTerminal : 0x00bNrChannels : 0x01 (1 channel)wChannelConfig : 0x0004 (C)iChannelNames : 0x00 (No String Descriptor)iTerminal : 0x00 (No String Descriptor)Data (HexDump) : 0C 24 02 01 01 01 00 01 04 00 00 00 .$..........Audio Control Feature Unit Descriptor --------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x06 (Feature Unit)bUnitID : 0x02 (2)bSourceID : 0x01 (1)bControlSize : 0x01 (1 byte per control): 0x01D0: Mute : 1D1: Volume : 0D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 0D7: Delay : 0: 0x02D0: Mute : 0D1: Volume : 1D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 0D7: Delay : 0iFeature : 0x00 (No String Descriptor)Data (HexDump) : 09 24 06 02 01 01 01 02 00 .$.......Audio Control Output Terminal Descriptor ------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x03 (Output Terminal)bTerminalID : 0x03wTerminalType : 0x0302 (Headphones)bAssocTerminal : 0x00 (0)bSourceID : 0x02 (2)iTerminal : 0x00 (No String Descriptor)Data (HexDump) : 09 24 03 03 02 03 00 02 00 .$.......Audio Control Input Terminal Descriptor -------bLength : 0x0C (12 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x02 (Input Terminal)bTerminalID : 0x04wTerminalType : 0x0201 (Microphone)bAssocTerminal : 0x00bNrChannels : 0x01 (1 channel)wChannelConfig : 0x0004 (C)iChannelNames : 0x00 (No String Descriptor)iTerminal : 0x00 (No String Descriptor)Data (HexDump) : 0C 24 02 04 01 02 00 01 04 00 00 00 .$..........Audio Control Feature Unit Descriptor --------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x06 (Feature Unit)bUnitID : 0x05 (5)bSourceID : 0x04 (4)bControlSize : 0x01 (1 byte per control): 0x43D0: Mute : 1D1: Volume : 1D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 1D7: Delay : 0: 0x00D0: Mute : 0D1: Volume : 0D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 0D7: Delay : 0iFeature : 0x00 (No String Descriptor)Data (HexDump) : 09 24 06 05 04 01 43 00 00 .$....C..Audio Control Selector Unit Descriptor --------bLength : 0x07 (7 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x05 (Selector Unit)bUnitID : 0x09bNrInPins : 0x01 (1 Input Pin): 0x05 (5)iSelector : 0x00 (No String Descriptor)Data (HexDump) : 07 24 05 09 01 05 00 .$.....Audio Control Output Terminal Descriptor ------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x03 (Output Terminal)bTerminalID : 0x06wTerminalType : 0x0101 (USB Streaming)bAssocTerminal : 0x02 (2)bSourceID : 0x09 (9)iTerminal : 0x00 (No String Descriptor)Data (HexDump) : 09 24 03 06 01 01 02 09 00 .$.......Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x03 (Interface 3)bAlternateSetting : 0x00bNumEndpoints : 0x00 (Default Control Pipe only)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x02 (Audio Streaming)bInterfaceProtocol : 0x00iInterface : 0x00 (No String Descriptor)Data (HexDump) : 09 04 03 00 00 01 02 00 00 .........Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x03 (Interface 3)bAlternateSetting : 0x01bNumEndpoints : 0x01 (1 Endpoint)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x02 (Audio Streaming)bInterfaceProtocol : 0x00iInterface : 0x00 (No String Descriptor)Data (HexDump) : 09 04 03 01 01 01 02 00 00 .........Audio Streaming Interface Descriptor ---------bLength : 0x07 (7 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x01 (AS_GENERAL)bTerminalLink : 0x01 (Terminal ID 1)bDelay : 0x01 (1 frame)wFormatTag : 0x0001 (PCM)Data (HexDump) : 07 24 01 01 01 01 00 .$.....Audio Streaming Format Type Descriptor --------bLength : 0x0B (11 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x02 (Format Type)bFormatType : 0x01 (FORMAT_TYPE_I)bNrChannels : 0x01 (1 channel)bSubframeSize : 0x02 (2 bytes per subframe)bBitResolution : 0x10 (16 bits per sample)bSamFreqType : 0x01 (supports 1 sample frequence): 0x03E80 (16000 Hz)Data (HexDump) : 0B 24 02 01 01 02 10 01 80 3E 00 .$.......>.Endpoint Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x05 (Endpoint Descriptor)bEndpointAddress : 0x02 (Direction=OUT EndpointID=2)bmAttributes : 0x0D (TransferType=Isochronous SyncType=Synchronous EndpointType=Data)wMaxPacketSize : 0x0020Bits 15..13 : 0x00 (reserved, must be zero)Bits 12..11 : 0x00 (0 additional transactions per microframe -> allows 1..1024 bytes per packet)Bits 10..0 : 0x20 (32 bytes per packet)bInterval : 0x01 (1 ms)bRefresh : 0x00bSynchAddress : 0x00Data (HexDump) : 09 05 02 0D 20 00 01 00 00 .... ....Audio Data Endpoint Descriptor ------------bLength : 0x07 (7 bytes)bDescriptorType : 0x25 (Audio Endpoint Descriptor)bDescriptorSubtype : 0x01 (General)bmAttributes : 0x00D0 : Sampling Freq : 0x00 (not supported)D1 : Pitch : 0x00 (not supported): Reserved : 0x00D7 : MaxPacketsOnly : 0x00 (no)bLockDelayUnits : 0x00 (Undefined)wLockDelay : 0x0000Data (HexDump) : 07 25 01 00 00 00 00 .%.....Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x04 (Interface 4)bAlternateSetting : 0x00bNumEndpoints : 0x00 (Default Control Pipe only)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x02 (Audio Streaming)bInterfaceProtocol : 0x00iInterface : 0x00 (No String Descriptor)Data (HexDump) : 09 04 04 00 00 01 02 00 00 .........Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x04 (Interface 4)bAlternateSetting : 0x01bNumEndpoints : 0x01 (1 Endpoint)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x02 (Audio Streaming)bInterfaceProtocol : 0x00iInterface : 0x00 (No String Descriptor)Data (HexDump) : 09 04 04 01 01 01 02 00 00 .........Audio Streaming Interface Descriptor ---------bLength : 0x07 (7 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x01 (AS_GENERAL)bTerminalLink : 0x06 (Terminal ID 6)bDelay : 0x01 (1 frame)wFormatTag : 0x0001 (PCM)Data (HexDump) : 07 24 01 06 01 01 00 .$.....Audio Streaming Format Type Descriptor --------bLength : 0x0B (11 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x02 (Format Type)bFormatType : 0x01 (FORMAT_TYPE_I)bNrChannels : 0x01 (1 channel)bSubframeSize : 0x02 (2 bytes per subframe)bBitResolution : 0x10 (16 bits per sample)bSamFreqType : 0x01 (supports 1 sample frequence): 0x03E80 (16000 Hz)Data (HexDump) : 0B 24 02 01 01 02 10 01 80 3E 00 .$.......>.Endpoint Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x05 (Endpoint Descriptor)bEndpointAddress : 0x82 (Direction=IN EndpointID=2)bmAttributes : 0x0D (TransferType=Isochronous SyncType=Synchronous EndpointType=Data)wMaxPacketSize : 0x0020Bits 15..13 : 0x00 (reserved, must be zero)Bits 12..11 : 0x00 (0 additional transactions per microframe -> allows 1..1024 bytes per packet)Bits 10..0 : 0x20 (32 bytes per packet)bInterval : 0x01 (1 ms)bRefresh : 0x00bSynchAddress : 0x00Data (HexDump) : 09 05 82 0D 20 00 01 00 00 .... ....Audio Data Endpoint Descriptor ------------bLength : 0x07 (7 bytes)bDescriptorType : 0x25 (Audio Endpoint Descriptor)bDescriptorSubtype : 0x01 (General)bmAttributes : 0x00D0 : Sampling Freq : 0x00 (not supported)D1 : Pitch : 0x00 (not supported): Reserved : 0x00D7 : MaxPacketsOnly : 0x00 (no)bLockDelayUnits : 0x00 (Undefined)wLockDelay : 0x0000Data (HexDump) : 07 25 01 00 00 00 00 .%.....Device Qualifier Descriptor (for Full-Speed) --------bLength : 0x0A (10 bytes)bDescriptorType : 0x06 (Device_qualifier Descriptor)bcdUSB : 0x200 (USB Version 2.00)bDeviceClass : 0xEF (Miscellaneous)bDeviceSubClass : 0x02bDeviceProtocol : 0x01 (IAD - Interface Association Descriptor)bMaxPacketSize0 : 0x40 (64 Bytes)bNumConfigurations : 0x01 (1 other-speed configuration)bReserved : 0x00Data (HexDump) : 0A 06 00 02 EF 02 01 40 01 00 .......@..Configuration Descriptor -------------------bLength : 0x09 (9 bytes)bDescriptorType : 0x02 (Configuration Descriptor)wTotalLength : 0x00CF (207 bytes)bNumInterfaces : 0x03 (3 Interfaces)bConfigurationValue : 0x01 (Configuration 1)iConfiguration : 0x00 (No String 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.....%.....IAD Descriptor --------------------bLength : 0x08 (8 bytes)bDescriptorType : 0x0B (Interface Association Descriptor)bFirstInterface : 0x02 (Interface 2)bInterfaceCount : 0x03 (3 Interfaces)The total number of interfaces (3) must be greater than or equal tothe highest linked interface number (base 2 + count 3 = 5)bFunctionClass : 0x01 (Audio)bFunctionSubClass : 0x02 (Audio Streaming)bFunctionProtocol : 0x00iFunction : 0x07 (String Descriptor 7)Language 0x0409 : "USB.Audio"Data (HexDump) : 08 0B 02 03 01 02 00 07 ........Interface Descriptor -----------------bLength : 0x09 (9 bytes)bDescriptorType : 0x04 (Interface Descriptor)bInterfaceNumber : 0x02 (Interface 2)bAlternateSetting : 0x00bNumEndpoints : 0x00 (Default Control Pipe only)bInterfaceClass : 0x01 (Audio)bInterfaceSubClass : 0x01 (Audio Control)bInterfaceProtocol : 0x00iInterface : 0x07 (String Descriptor 7)Language 0x0409 : "USB.Audio"Data (HexDump) : 09 04 02 00 00 01 01 00 07 .........Audio Control Interface Header Descriptor ------bLength : 0x0A (10 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x01 (Header)bcdADC : 0x0100wTotalLength : 0x004D (77 bytes)bInCollection : 0x02: 0x03: 0x04Data (HexDump) : 0A 24 01 00 01 4D 00 02 03 04 .$...F....Audio Control Input Terminal Descriptor -------bLength : 0x0C (12 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x02 (Input Terminal)bTerminalID : 0x01wTerminalType : 0x0101 (USB Streaming)bAssocTerminal : 0x00bNrChannels : 0x01 (1 channel)wChannelConfig : 0x0004 (C)iChannelNames : 0x00 (No String Descriptor)iTerminal : 0x00 (No String Descriptor)Data (HexDump) : 0C 24 02 01 01 01 00 01 04 00 00 00 .$..........Audio Control Feature Unit Descriptor --------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x06 (Feature Unit)bUnitID : 0x02 (2)bSourceID : 0x01 (1)bControlSize : 0x01 (1 byte per control): 0x01D0: Mute : 1D1: Volume : 0D2: Bass : 0D3: Mid 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: 0x00 (No String Descriptor)Data (HexDump) : 0C 24 02 04 01 02 00 01 04 00 00 00 .$..........Audio Control Feature Unit Descriptor --------bLength : 0x09 (9 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x06 (Feature Unit)bUnitID : 0x05 (5)bSourceID : 0x04 (4)bControlSize : 0x01 (1 byte per control): 0x43D0: Mute : 1D1: Volume : 1D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 1D7: Delay : 0: 0x00D0: Mute : 0D1: Volume : 0D2: Bass : 0D3: Mid : 0D4: Treble : 0D5: Graphic Equalizer : 0D6: Automatic Gain : 0D7: Delay : 0iFeature : 0x00 (No String Descriptor)Data (HexDump) : 09 24 06 05 04 01 43 00 00 .$....C..Audio Control Selector Unit Descriptor --------bLength : 0x07 (7 bytes)bDescriptorType : 0x24 (Audio Interface Descriptor)bDescriptorSubtype : 0x05 (Selector Unit)bUnitID : 0x09bNrInPins : 0x01 (1 Input Pin): 0x05 (5)iSelector : 0x00 (No String Descriptor)Data (HexDump) : 07 24 05 09 01 05 00 .$.....Audio Control 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见九.抓包文件分享,不再赘述
参见前面扬声器和麦克风的实例
参见前面扬声器和麦克风的实例
参见前面扬声器和麦克风的实例
UAC_SPK_MIC.upv
可以使用USB Packet Viewer这个软件回放,方便查看枚举和数据传输过程。
链接：https://pan.baidu.com/s/1ANSHlXRQC_mTyram9qbHAg?pwd=btcj
提取码：btcj
以上分享了一个完整的UAC的扬声器+麦克风的实例，描述符可以直接使用，其他参考单独的扬声器和麦克风的实现即可。USB描述符的正确是能顺利枚举的首要条件，枚举完成了，基本就成功了一半了。有时候描述符一丁点不对就会导致枚举失败，所以有时候这些问题会困扰很久，有一个正确的描述符作为参考显得很有价值。故特分享此案例。
