GL850 Datasheet, PDF (27/40 Pages) List of Unclassifed Manufacturers – USB 2.0 4-PORT HUB Controller

GL850 USB 2.0 4-Port HUB Controller
5.4 Descriptors
Descriptors contain all the information about the USB2.0 hub. Host asks different types of descriptors by
different GET_DESCRIPTOR commands. Hub will reply to different GET_DESCRIPTOR the associated
descriptors to let host know how to configure the hub. For an USB2.0 hub, the descriptors are:
Device Descriptor
Device Qualifier Descriptor
Configuration Descriptor
Interface Descriptor
Endpoint Descriptor
Other Speed Configuration Descriptor
Hub Class-specific Descriptor
String Descriptor
Descriptors replied are different between full speed and high speed for an USB2.0 hub. Once an USB2.0
hub is plugged into a host/hub, it needs to firstly decide the host/hub is an USB1.1 host/hub or an
USB2.0 host/hub. If the host/hub being plugged is an USB1.1 hub, GL850 replies to the host the full
speed descriptors defined in section 6.2.1. Otherwise, GL850 replies the high speed descriptors defined
in section 6.2.2. For hub class-specific descriptor, there’s no difference between full speed and high speed.
5.4.1 Full Speed Case
5.4.1.1 Device Descriptor
Hub returns Device Descriptor when GET_DESCRIPTOR (DEVICE) command is requested.
Table 5.4 - Device Descriptor for Full Speed
Offset
Field
Value
Description
0 bLength
12h 18 bytes for this descriptor
1 bDescriptorType
01h Device descriptor type
2 bcdUSB
0200h USB2.0 compliance
4 bDeviceClass
09h Hub class code
5 bDeviceSubClass
00h Subclass code
6 bDeviceProtocol
00h Protocol code
7 bMaxPacktSize0
8 idVendor
10 idProduct
12 bcdDevice
40h
Max. packet size of
endpoint0
05E3h
Vendor ID of Genesys
Logic Inc.
0660h
Product ID of Genesys
Logic Inc.
xxxxh Version Control
14 iManufacturer
00h Index of vendor string
15 idProduct
01h Index of product string
16 iSerialNumber
00h Index of serial number
17 bNumConfigurations 01h Number of configuration
I/O
EEPROM
Configuration Configuration
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Y
-
Y
-
Y
-
Y
-
Y
-
Y
-
-
©2000-2003 Genesys Logic Inc.—All rights reserved.
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