LAN9500 Datasheet, PDF (32/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
5.3.1.6.2
Configuration Descriptor
The Configuration Descriptor is initialized based on values stored in EEPROM. Table 5-5 shows the default Configura-
tion Descriptor values. These values are used for both Full-Speed and Hi-Speed operation.
TABLE 5-5: CONFIGURATION DESCRIPTOR
Offset
Field
Size
(Bytes)
Default
Value
Loaded
from
EEPROM
Description
00h bLength
1
09h
Note 5-5 Size of the Configuration Descriptor in
bytes (9 bytes)
01h bDescriptorType
1
02h
Note 5-6 Configuration Descriptor (0x02)
02h wTotalLength
2
0027h
Note 5-5 Total length in bytes of data returned
(39 bytes)
04h bNumInterfaces
1
01h
Note 5-5 Number of Interfaces
05h bConfigurationValue
1
01h
Note 5-5 Value to use as an argument to select
this configuration
06h iConfiguration
1
00h
Yes
Index of String Descriptor describing
this configuration
07h bmAttributes
1
A0h
Yes Bus powered and remote wakeup
enabled.
08h bMaxPower
1
Note 5-7
Yes
Maximum Power Consumption is 500
mA.
Note 5-5 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 5-6
The descriptor type for Configuration Descriptors specified in EEPROM is a “don’t care” and is always
overwritten by hardware as 0x02.
Note 5-7 Default value is 01h in Self Powered mode and FAh in Bus Powered mode.
Note: The PWR_SEL and RMT_WKP straps affect the default value of bmAttributes.
5.3.1.6.3
Interface Descriptor 0 Default
Table 5-6 shows the default value for Interface Descriptor 0. This descriptor is initialized based on values stored in
EEPROM.
TABLE 5-6: INTERFACE DESCRIPTOR 0
Offset
Field
Size
(Bytes)
Default
Value
Loaded
From
EEPROM
Description
00h bLength
1
09h
Note 5-8 Size of Descriptor in Bytes (9 Bytes
01h bDescriptorType
1
04h
Note 5-8 Interface Descriptor (0x04)
02h bInterfaceNumber
1
00h
Note 5-8 Number identifying this Interface
03h bAlternateSetting
1
00h
Note 5-8 Value used to select alternative setting
04h bNumEndpoints
1
03h
Note 5-8 Number of Endpoints used for this
interface (Less endpoint 0)
05h bInterfaceClass
1
FFh
Yes Class Code
06h bInterfaceSubClass
1
00h
Yes
Subclass Code
07h bInterfaceProtocol
1
FFh
Yes Protocol Code
08h iInterface
1
00h
Yes
Index of String Descriptor Describing
this interface
Note 5-8 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.
DS00001875A-page 32
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