gl850 ETC-unknow, gl850 Datasheet - Page 27

• Manufacturer Part Number: gl850
• Description: Usb 2.0 4-port Hub Controller
• Manufacturer: ETC-unknow

5.4 Descriptors
5.4.1 Full Speed Case
5.4.1.1 Device Descriptor
©2000-2003 Genesys Logic Inc.—All rights reserved.
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:
Hub returns Device Descriptor when GET_DESCRIPTOR (DEVICE) command is requested.
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.
Offset
10
12
14
15
16
17
0
1
2
4
5
6
7
8
Device Descriptor
Device Qualifier Descriptor
Configuration Descriptor
Interface Descriptor
Endpoint Descriptor
Other Speed Configuration Descriptor
Hub Class-specific Descriptor
String Descriptor
bLength
bDescriptorType
bcdUSB
bDeviceClass
bDeviceSubClass
bDeviceProtocol
bMaxPacktSize0
idVendor
idProduct
bcdDevice
iManufacturer
idProduct
iSerialNumber
bNumConfigurations
Field
Table 5.4 - Device Descriptor for Full Speed
05E3h
0200h USB2.0 compliance
0660h
Value
xxxxh Version Control
12h
01h
09h
00h
00h
40h
00h
01h
00h
01h
18 bytes for this descriptor
Device descriptor type
Hub class code
Subclass code
Protocol code
Max. packet size of
endpoint0
Vendor ID of Genesys
Logic Inc.
Product ID of Genesys
Logic Inc.
Index of vendor string
Index of product string
Index of serial number
Number of configuration
Description
GL850 USB 2.0 4-Port HUB Controller
Configuration
I/O
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Configuration
EEPROM
Y
Y
Y
Y
Y
Y
-
-
-
-
-
-
-
-
Page 27