5&'86%

,QWHJUDWHG9.IOH[0RGHP'HYLFH6HWVZLWK86%,QWHUIDFH



0'

Table 3. Device Descriptors

Offset

Field

Size

Value

Default

Description

0

bLength

1

Number

12

Size of this descriptor in bytes.

1

bDescriptorType

1

Constant

01

DEVICE Descriptor Type.

2

bcdUSB

2

BCD

0100

USB Specification Release Number in Binary-Coded Decimal (i.e.,

2.10 is 0x210). This field identifies the release of the USB

Specification that the device and its descriptors are compliant with.

4

bDeviceClass

1

Class

00

Class code (assigned by USB).

If this field is reset to 0, each interface within a configuration

specifies its own class information and the various interfaces operate

independently.

If this field is set to a value between 1 and 0xFE, the device supports

different class specifications on different interfaces and the

interfaces may not operate independently. This value identifies the

class definition used for the aggregate interfaces. (For example, a

CD-ROM device with audio and digital data interfaces that require

transport control to eject CDs or start them spinning.)

If this field is set to 0xFF, the device class is vendor specific.

5

bDeviceSubClass

1

SubClass

00

Subclass code (assigned by USB).

These codes are qualified by the value of the bDeviceClass field.

If the

bDeviceClass field is reset to 0, this field must also be reset to

0.

If the

bDeviceClass field is not set to 0xFF, all values are reserved

for assignment by USB.

6

bDeviceProtocol

1

Protocol

00

Protocol code (assigned by USB). These codes are qualified by the

value of the

bDeviceClass and the bDeviceSubClass fields. If a

device supports class-specific protocols on a device basis as

opposed to an interface basis, this code identifies the protocols that

the device uses as defined by the specification of the device class.

If this field is reset to 0, the device does not use class specific

protocols on a device basis. However, it may use class specific

protocols on an interface basis.

If this field is set to 0xFF, the device uses a vendor specific protocol

on a device basis.

7

bMaxPacketSize0

1

Number

08

Maximum packet size for endpoint zero (only 8, 16, 32, or 64 are

valid).

8

idVendor

2

ID

1394

Vendor ID (assigned by USB).

10

idProduct

2

ID

7470

Product ID (assigned by the manufacturer).

12

bcdDevice

2

BCD

0100

Device release number in binary-coded decimal.

14

iManufacturer

1

Index

01

Index of string descriptor describing manufacturer.

15

iProduct

1

Index

02

Index of string descriptor describing product.

16

iSerialNumber

1

Index

03

Index of string descriptor describing the device’s serial number.

17

bNumConfigurations

1

Number

02

Number of possible configurations.