AN249 데이터 시트보기 (PDF) - Silicon Laboratories

부품명

상세내역

제조사

AN249

HUMAN INTERFACE DEVICE TUTORIAL

Silicon Laboratories 

5.4.1. Device Descriptor

The template defines the Device Descriptor as follows:

{

18,

// bLength

0x01,

// bDescriptorType

0x1001,

0x00,

0x00,

// bcdUSB

// bDeviceClass

// bDeviceSubClass

0x00,

// bDeviceProtocol

EP0_PACKET_SIZE, // bMaxPacketSize0

0xC410, // idVendor

0x0000, // idProduct

0x0000, // bcdDevice

0x00,

0x00,

0x00,

// iManufacturer

// iProduct

// iSerialNumber

0x01

// bNumConfigurations

};

AN249

18,

// bLength

The first item describes the descriptor length and should be common to all USB Device Descriptors.

0x01,

// bDescriptorType

0x01 is the constant one-byte designator for Device descriptors and should be common to all device descriptors.

0x1001,

// bcdUSB

This BCD-encoded two-byte item tells the system which USB specification release guidelines the device follows.

This number might need to be altered in devices that take advantage of additions or changes included in future

revisions of the USB specification, as the host will use this item to help determine what driver to load for the device.

0x00,

// bDeviceClass

If the USB device class is to be defined inside the device descriptor, this item would contain a constant defined in

the USB specification. However, this firmware template assumes that the device will be defined in other

descriptors. Device classes defined in other descriptors should set the Device Class item in the Device Descriptor

to 0x00.

0x00,

// bDeviceSubClass

If the Device Class item discussed above is set to 0x00, then the Device Sub Class item should also be set to

0x00. This item can tell the host information about the device’s subclass setting.

0x00,

// bDeviceProtocol

This item can tell the host whether the device supports high speed transfers. If the above two items are set to 0x00,

this one should also be set to 0x00.

EP0_PACKET_SIZE,

// bMaxPacketSize0

Rev. 0.2

11

Share Link: