LAN9500 Datasheet, PDF (35/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
5.3.1.6.8
Device Qualifier Descriptor
The fields in this descriptor are derived from Device Descriptor information that is stored in the EEPROM.
TABLE 5-11: DEVICE QUALIFIER DESCRIPTOR
Offset
Field
Size
(Bytes)
Default
Value
Loaded
from
EEPROM
Description
00h bLength
1
01h bDescriptorType
1
02h bcdUSB
2
04h bDeviceClass
1
05h bDeviceSubClass
1
06h bDeviceProtocol
1
07h bMaxPacketSize0
1
08h bNumConfigurations
1
09h Reserved
1
0Ah
06h
0200h
FFh
00h
FFh
40h
01h
00h
No
No
Note 5-14
Yes
Yes
Yes
Note 5-14
Note 5-14
No
Size of Descriptor in bytes (10 bytes)
Device Qualifier Descriptor (0x06)
USB Specification Number which
device complies to.
Class Code
Subclass Code
Protocol Code
Maximum Packet Size
Number of Other-Speed Configurations
Must be zero
Note:
EEPROM values are from the Device Descriptor (including any EEPROM override) at the opposite HS/FS
operating speed. I.e., if the current operating speed is HS, then Device Qualifier data is based on the FS
Device Descriptor, and vice-versa.
Note 5-14
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.
5.3.1.6.9
String Descriptors
String Index = 0 (LANGID)
TABLE 5-12: LANGID STRING DESCRIPTOR
Offset
Field
Size
(Bytes)
Default
Value
Loaded
from
EEPROM
Description
00h bLength
1
04h
No
Size of LANGID Descriptor in bytes (4
bytes)
01h bDescriptorType
1
03h
No
String Descriptor (0x03)
02h LANGID
2
None
Yes
Must be set to 0x0409 (US English).
Note 1: If there is no valid/enabled EEPROM, or if all string lengths in the EEPROM are 0, then there are no strings,
so any host attempt to read the LANGID string will return stall in the Data Stage of the Control Transfer.
If there is a valid/enabled EEPROM, and if at least one of the string lengths in the EEPROM is not 0, then
the value contained at EEPROM addresses 0x0A-0x0B will be returned. These must be 0x0409 to allow for
proper device operation.
2: The device ignores the LANGID field in Control Read’s of Strings, and will not return the String (if it exists),
regardless of whether the requested LANGID is 0x0409 or not.
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DS00001875A-page 35