4-Port USB2.0 Hub Controller
Datasheet
Revision 1.63 (10-14-04)
Page 34
SMSC USB20H04
DATASHEET
Table 9.7 - Interface Descriptor (present if multiple-TT)
OFFSET
HIGH
SPEED
09h
FIELD NAME
DESCRIPTION
0
bLength
bDescriptorType
bInterfaceNumber
Size of this descriptor in bytes
1
2
04h
00h
INTERFACE Descriptor Type
Number of this interface
Value used to select this alternate setting for
the interface
3
01h
bAlternateSetting
4
01h
bNumEndpoints
Number of endpoints used by this interface (not
including endpoint 0)
5
6
09h
00h
bInterfaceClass
bInterfaceSubClass
Class code assigned by USB for Hubs
Subclass code assigned by USB
7
02h
bInterfaceProtcol
Protocol code assigned by USB
8
00h
bInterface
Index of string descriptor describing this
configuration (string not supported)
Table 9.8 - On-The-GO (OTG) Descriptor
OFFSET
FULL
03h
FIELD NAME
DESCRIPTION
0
03h
bLength
bDescriptorType
Size of this descriptor in bytes
1
09h
09h
OTG Descriptor Type
Attribute Fields:
D[7:2] = Reserved
D1: HNP Support (not supported)
2
01h
01h
wMaxPacketSize
D0: SRP Support.
Table 9.9 - Class-Specific Hub Descriptor (Full-Speed and High-Speed)
OFFSET
0
1
2
FIELD NAME
Length
Descriptor Type
NbrPorts
VALUE
09h
29h
user
DESCRIPTION
Size of this Descriptor.
Hub Descriptor Type.
Number of downstream facing ports this Hub
supports. Derived from OEM value defined in
EEPROM or SMBus load. See Section 11.23.2.1 in
the USB Specification.
Note: If Dynamic Power is enabled, and the
SELF_PWR pin is low (indicating Bus Power
Operation), then ports 3 & 4 are not available and
either a value of 1 is reported if the OEM value is 1
or a value of 2 is reported if the OEM value is 2, 3
or 4.
Defines several characteristics that are derived
from OEM values. Also defines TT Think Time
(fixed at a value of 00b for 8FS bit times max).
Time (in 2 ms intervals) from the time the power-on
sequence begins on a port until power is good on
that port. Derived from OEM value.
3,4
HubCharacteristics
user
5
PwrOn2PwrGood
user