LAN9500 Datasheet, PDF (31/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
5.3.1.6 USB Descriptors
The following subsections describe the USB descriptors.
5.3.1.6.1
Device Descriptor
The Device Descriptors are initialized based on values stored in EEPROM. Table 5-4 shows the default Device Descrip-
tor values. These values are used for both Full-Speed and Hi-Speed operation.
TABLE 5-4: DEVICE DESCRIPTOR
Offset
Field
Size
(Bytes)
Default
Value
Loaded
from
EEPROM
Description
00h bLength
1
12h
Note 5-1 Size of the Descriptor in Bytes (18
bytes)
01h bDescriptorType
1
01h
Note 5-1 Device Descriptor (0x01)
02h bcdUSB
2
0200h
Note 5-2 USB Specification Number which
device complies to.
04h bDeviceClass
1
FFh
Yes
Class Code
05h bDeviceSubClass
1
00h
Yes
Subclass Code
06h bDeviceProtocol
1
FFh
Yes Protocol Code
07h bMaxPacketSize
1
40h
Note 5-2 Maximum Packet Size for Endpoint 0
08h IdVendor
2
0424h
Yes
Vendor ID
0Ah IdProduct
2
Note 5-3
Yes
Product ID
0Ch bcdDevice
2
Note 5-4
Yes
Device Release Number
0Eh iManufacturer
1
00h
Yes
Index of Manufacturer String Descriptor
0Fh iProduct
1
00h
Yes
Index of Product String Descriptor
10h iSerialNumber
1
00h
Yes
Index of Serial Number String
Descriptor
11h bNumConfigurations
1
01h
Note 5-2 Number of Possible Configurations
Note 5-1
The descriptor length and descriptor type for Device Descriptors specified in EEPROM are “don’t
cares” and are always overwritten by hardware as 0x12 and 0x01, respectively.
Note 5-2
Value is loaded from EEPROM, but must be equal to the Default Value in order to comply with the
USB 2.0 Specification and provide for normal device operation. Specification of any other value will
result in unwanted behavior and untoward operation.
Note 5-3 Product IDs are:
Product
ID
LAN9500/LAN9500i
9500h
LAN9500A/LAN9500Ai
9E00h
Note 5-4
Default value is dependent on device release. MSB matches the device release and LSB hardcoded
to 00h. The initial release value is 01h.
 2010 - 2015 Microchip Technology Inc.
DS00001875A-page 31