USB笔记标准设备请求 Standard Device Requests

这里主要列举出所有设备定义的标准设备请求。分别概述了标准设备请求(Standard Device Requests)和给出了标准请求代码(Standard Request Codes)和描述符类型(Descriptor Types)。概念部分主要从各种USB协议中整理，涵盖范围从USB 2.0到 USB 3.2协议。注意并不是所有协议都支持所有的标准设备请求，具体不同协议的差异可以参照附录。

标准设备请求(Standard Device Requests)，例如下图的Get Descriptor就是一个USB设备标准请求。

对于标准设备请求，设备要求即使在尚未分配地址或尚未配置的时候，也应该响应标准设备请求。如果标准请求定义了一个可以修改的持久性参数，该参数的重置值或默认值为零，除非该参数另有规定。

标准设备请求 Standard Device Requests

下表是标准设备请求，概述了标准设备请求的基本情况。

bmRequestType	bRequest	wValue		wIndex		wLength	Data

00000000B 00000001B 00000010B	CLEAR_FEATURE	Feature Selector		Zero Interface Endpoint		Zero	None

10000000B	GET_CONFIGURATION	Zero		Zero		One	Configuration Value

10000000B	GET_DESCRIPTOR	Descriptor Type and Descriptor Index		Zero or Language ID		Descriptor Length	Descriptor

10000001B	GET_INTERFACE	Zero		Interface		One	Alternate Interface

10000000B 10000001B 10000010B	GET_STATUS	Zero	Status Type	Zero Interface Endpoint		Two	Device, Interface, or Endpoint Status

00000000B	SET_ADDRESS	Device Address		Zero		Zero	None

00000000B	SET_CONFIGURATION	Configuration Value		Zero		Zero	None

00000000B	SET_DESCRIPTOR	Descriptor Type and Descriptor Index		Zero or Language ID		Descriptor Length	Descriptor

00000000B 00000001B 00000010B	SET_FEATURE	Feature Selector		Options	Zero Interface Endpoint	Zero	None

00000001B	SET_INTERFACE	Alternate Setting		Interface		Zero	None

00000000B	SET_ISOCH_DELAY	Delay in ns		Zero		Zero	None

00000000B	SET_SEL	Zero		Zero		Six	Exit Latency Values

10000010B	SYNCH_FRAME	Zero		Endpoint		Two	Frame Number

标准请求代码 Standard Request Codes

下表是标准请求代码，对应着标准设备请求中的bRequest字段。

bRequest	Value
GET_STATUS	0
CLEAR_FEATURE	1
Reserved for future use	2
SET_FEATURE	3
Reserved for future use	4
SET_ADDRESS	5
GET_DESCRIPTOR	6
SET_DESCRIPTOR	7
GET_CONFIGURATION	8
SET_CONFIGURATION	9
GET_INTERFACE	10
SET_INTERFACE	11
SYNCH_FRAME	12
SET_ENCRYPTION	13
GET_ENCRYPTION	14
SET_HANDSHAKE	15
GET_HANDSHAKE	16
SET_CONNECTION	17
SET_SECURITY_DATA	18
GET_SECURITY_DATA	19
SET_WUSB_DATA	20
LOOPBACK_DATA_WRITE	21
LOOPBACK_DATA_READ	22
SET_INTERFACE_DS	23
SET_SEL	48
SET_ISOCH_DELAY	49

描述符类型 Descriptor Types

下表是描述符类型，对应着部分标准设备请求中的wValue字段中的Descriptor Type。

Descriptor Types	Value
DEVICE	1
CONFIGURATION	2
STRING	3
INTERFACE	4
ENDPOINT	5
Reserved	6
Reserved	7
INTERFACE_POWER	8
OTG	9
DEBUG	10
INTERFACE_ASSOCIATION	11
BOS	15
DEVICE CAPABILITY	16
SUPERSPEED_USB_ENDPOINT_COMPANION	48
SUPERSPEEDPLUS_ISOCHRONOUS_ENDPOINT_COMPANION	49

标准特性选择器 Standard Feature Selectors

下表是标准特性选择器(feature selector)，表中给出了feature selector的接收端(Recipient)和feature selector对应的数值(value)，其中数值(value)就是对应着部分标准设备请求中的wValue字段中的Feature selector。

特性选择器(feature selectors)用于启用或设置特定于设备(device)、接口(interface)或端点(endpoint)的特性(features)。例如远程唤醒(remote wakeup)功能。

Feature Selector	Recipient	Value
ENDPOINT_HALT	Endpoint	0
FUNCTION_SUSPEND	Interface	0
DEVICE_REMOTE_WAKEUP	Device	1
TEST_MODE	Device	2
b_hnp_enable	Device	3
a_hnp_support	Device	4
a_alt_hnp_support	Device	5
WUSB_DEVICE	Device	6
U1_ENABLE	Device	48
U2_ENABLE	Device	49
LTM_ENABLE	Device	50
B3_NTF_HOST_REL	Device	51

B3_RSP_ENABLE	Device	52
LDM_ENABLE	Device	53

如果向设备发出了不支持或无效的请求(request)，设备会在请求的数据阶段(Data stage)或状态阶段(Status stage)返回一个STALL事务包(STALL Transaction Packet)。如果设备在设置阶段(Setup stage)检测到错误，则设备最好在数据或状态阶段中较早的阶段返回一个STALL事务包。接收不支持或无效的请求不会导致控制管道(control pipe)上的停止特性(Halt feature)被设置。如果由于任何原因，设备因错误条件而无法通过其默认控制管道进行通信，则应重置设备以清除该条件并重新启动默认控制管道。

附录

USB2.0 Standard Device Requests

USB2.0所支持的Standard Device Requests会比上面的少，如下表：

USB2.0 Standard Device Requests

bmRequestType	bRequest	wValue	wIndex	wLength	Data
00000000B 00000001B 00000010B	CLEAR_FEATURE	Feature Selector	Zero Interface Endpoint	Zero	None
10000000B	GET_CONFIGURATION	Zero	Zero	One	Configuration Value
10000000B	GET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID	Descriptor Length	Descriptor
10000001B	GET_INTERFACE	Zero	Interface	One	Alternate Interface
10000000B 10000001B 10000010B	GET_STATUS	Zero	Zero Interface Endpoint	Two	Device, Interface, or Endpoint Status
00000000B	SET_ADDRESS	Device Address	Zero	Zero	None
00000000B	SET_CONFIGURATION	Configuration Value	Zero	Zero	None
00000000B	SET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID	Descriptor Length	Descriptor
00000000B 00000001B 00000010B	SET_FEATURE	Feature Selector	Zero Interface Endpoint	Zero	None
00000001B	SET_INTERFACE	Alternate Setting	Interface	Zero	None
10000010B	SYNCH_FRAME	Zero	Endpoint	Two	Frame Number

USB2.0 Standard Request Codes

bRequest	Value
GET_STATUS	0
CLEAR_FEATURE	1
Reserved for future use	2
SET_FEATURE	3
Reserved for future use	4
SET_ADDRESS	5
GET_DESCRIPTOR	6
SET_DESCRIPTOR	7
GET_CONFIGURATION	8
SET_CONFIGURATION	9
GET_INTERFACE	10
SET_INTERFACE	11
SYNCH_FRAME	12

USB2.0 Descriptor Types

Descriptor Types	Value
DEVICE	1
CONFIGURATION	2
STRING	3
INTERFACE	4
ENDPOINT	5
DEVICE_QUALIFIER	6
OTHER_SPEED_CONFIGURATION	7
INTERFACE_POWER	8

USB2.0 Standard Feature Selectors

Feature Selector	Recipient	Value
DEVICE_REMOTE_WAKEUP	Device	1
ENDPOINT_HALT	Endpoint	0
TEST_MODE	Device	2

USB3.0 Standard Device Requests

bmRequestType	bRequest	wValue	wIndex		wLength	Data

00000000B 00000001B 00000010B	CLEAR_FEATURE	Feature Selector	Zero Interface Endpoint		Zero	None

10000000B	GET_CONFIGURATION	Zero	Zero		One	Configuration Value

10000000B	GET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID		Descriptor Length	Descriptor

10000001B	GET_INTERFACE	Zero	Interface		One	Alternate Interface

10000000B 10000001B 10000010B	GET_STATUS	Zero	Zero Interface Endpoint		Two	Device, Interface, or Endpoint Status

00000000B	SET_ADDRESS	Device Address	Zero		Zero	None

00000000B	SET_CONFIGURATION	Configuration Value	Zero		Zero	None

00000000B	SET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID		Descriptor Length	Descriptor

00000000B 00000001B 00000010B	SET_FEATURE	Feature Selector	Zero Interface Endpoint	Suspend Options	Zero	None

00000001B	SET_INTERFACE	Alternate Setting	Interface		Zero	None

00000000B	SET_ISOCH_DELAY	Delay in ns	Zero		Zero	None

00000000B	SET_SEL	Zero	Zero		Six	Exit Latency Values

10000010B	SYNCH_FRAME	Zero	Endpoint		Two	Frame Number

USB3.0 Standard Request Codes

bRequest	Value
GET_STATUS	0
CLEAR_FEATURE	1
Reserved for future use	2
SET_FEATURE	3
Reserved for future use	4
SET_ADDRESS	5
GET_DESCRIPTOR	6
SET_DESCRIPTOR	7
GET_CONFIGURATION	8
SET_CONFIGURATION	9
GET_INTERFACE	10
SET_INTERFACE	11
SYNCH_FRAME	12
SET_SEL	48
SET_ISOCH_DELAY	49

USB3.0 Descriptor Types

Descriptor Types	Value
DEVICE	1
CONFIGURATION	2
STRING	3
INTERFACE	4
ENDPOINT	5
Reserved	6
Reserved	7
INTERFACE_POWER	8
OTG	9
DEBUG	10
INTERFACE_ASSOCIATION	11
BOS	15
DEVICE CAPABILITY	16
SUPERSPEED_USB_ENDPOINT_COMPANION	48

USB3.0 Standard Feature Selectors

Feature Selector	Recipient	Value
ENDPOINT_HALT	Endpoint	0
FUNCTION_SUSPEND	Interface	0
U1_ENABLE	Device	48
U2_ENABLE	Device	49
LTM_ENABLE	Device	50

USB3.1 & USB3.2 Standard Device Requests

同正文部分。

USB1.1 Standard Device Requests

bmRequestType	bRequest	wValue	wIndex	wLength	Data
00000000B 00000001B 00000010B	CLEAR_FEATURE	Feature Selector	Zero Interface Endpoint	Zero	None
10000000B	GET_CONFIGURATION	Zero	Zero	One	Configuration Value
10000000B	GET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID	Descriptor Length	Descriptor
10000001B	GET_INTERFACE	Zero	Interface	One	Alternate Interface
10000000B 10000001B 10000010B	GET_STATUS	Zero	Zero Interface Endpoint	Two	Device, Interface, or Endpoint Status
00000000B	SET_ADDRESS	Device Address	Zero	Zero	None
00000000B	SET_CONFIGURATION	Configuration Value	Zero	Zero	None
00000000B	SET_DESCRIPTOR	Descriptor Type and Descriptor Index	Zero or Language ID	Descriptor Length	Descriptor
00000000B 00000001B 00000010B	SET_FEATURE	Feature Selector	Zero Interface Endpoint	Zero	None
00000001B	SET_INTERFACE	Alternate Setting	Interface	Zero	None
10000010B	SYNCH_FRAME	Zero	Endpoint	Two	Frame Number

USB1.1 Standard Request Codes

bRequest	Value
GET_STATUS	0
CLEAR_FEATURE	1
Reserved for future use	2
SET_FEATURE	3
Reserved for future use	4
SET_ADDRESS	5
GET_DESCRIPTOR	6
SET_DESCRIPTOR	7
GET_CONFIGURATION	8
SET_CONFIGURATION	9
GET_INTERFACE	10
SET_INTERFACE	11
SYNCH_FRAME	12

USB1.1 Descriptor Types

Descriptor Types	Value
DEVICE	1
CONFIGURATION	2
STRING	3
INTERFACE	4
ENDPOINT	5

USB1.1 Standard Feature Selectors

Feature Selector	Recipient	Value
DEVICE_REMOTE_WAKEUP	Device	1
ENDPOINT_HALT	Endpoint	0

[参考资料]

Universal Serial Bus Specification Revision 1.1

Universal Serial Bus Specification Revision 2.0

Universal Serial Bus 3.0 Specification

Universal Serial Bus 3.1 Specification

Universal Serial Bus 3.2 Specification

USB Complete, 5th Edition

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