
GL850 USB 2.0 4-Port HUB Controller
2000-2003 Genesys Logic Inc.—All rights reserved.
Page 28
5.4.1.2 Device Qualifier Descriptor
Hub returns Device Qualifier Descriptor when GET_DESCRIPTOR (DEVICE_QUALIFIER) command is
issued from host.
Table 5.5 - Device Qualifier for Full Speed
Offset
Field
Value
Description
I/O
Configuration
EEPROM
Configuration
0
bLength
0Ah 10 bytes for this descriptor
Device qualifier descriptor
type
0200h USB2.0 compliance
-
-
1
bDescriptorType
06h
-
-
2
bcdUSB
-
-
4
bDeviceClass
09h
Hub class code
-
-
5
bDeviceSubClass
00h
Subclass code
-
-
6
bDeviceProtocol
01h
Single TT
Max. packet size for
endpoint0 of other speed
Number of other speed
config.
Reserved for future use
-
-
7
bMaxPacketSize0
40h
-
-
8
bNumConfigurations
01h
-
-
9
bReserved
00h
-
-
5.4.1.3 Configuration Descriptor
When host issues GET_DESCRIPTOR (CONFIGURATION) command to the hub, hub will return
Configuration Descriptor, Interface Descriptor, and Endpoint Descriptor in combination to the host.
Table 5.6 - Configuration Descriptor for Full Speed
Offset
Field
Value
Description
I/O
Configuration
EEPROM
Configuration
0
bLength
09h
9 bytes for this descriptor
Configuration descriptor
type
0019h Total 25 bytes
-
-
1
bDescriptorType
02h
-
-
2
wTotalLength
-
-
4
bNumberInterface
01h
Number of interfaces
-
-
5
bConfigurationValue
01h
Configuration value
-
-
6
iConfiguration
00h
Index of string descriptor
Can switch between self
power and bus power
Max. power = 100 mA
-
-
7
bmAttribute
E0h
-
-
8
bMaxPower
32h
-
-