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4-Port USB 2.0 Controller
Datasheet
SMSC USB20H04 Page 31 Revision 1.63 (03-30-07)
DATASHEET
Table 9.7 - Interface Descriptor (present if multiple-TT)
OFFSET
HIGH
SPEED
FIELD NAME DESCRIPTION
0 09h
bLength
Size of this descriptor in bytes
1 04h bDescriptorType INTERFACE Descriptor Type
2 00h bInterfaceNumber Number of this interface
3 01h bAlternateSetting
Value used to select this alternate setting for
the interface
4 01h bNumEndpoints
Number of endpoints used by this interface (not
including endpoint 0)
5 09h bInterfaceClass Class code assigned by USB for Hubs
6 00h bInterfaceSubClass 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
SPEED
HIGH SPEED FIELD NAME DESCRIPTION
0 03h 03h
bLength
Size of this descriptor in bytes
1 09h 09h bDescriptorType 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 FIELD NAME VALUE DESCRIPTION
0 Length 09h Size of this Descriptor.
1 Descriptor Type 29h Hub Descriptor Type.
2 NbrPorts user 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.
3,4 HubCharacteristics user 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).
5 PwrOn2PwrGood user 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.