EZ-USB Datasheet, PDF (89/334 Pages) Cypress Semiconductor – The EZ-USB USB Integrated Circuit

Table 5-10. USB Default Configuration Descriptor
Offset
Field
0 bLength
1 bDescriptorType
2 wTotalLength (L)
3 wTotalLength (H)
4 bNumInterfaces
5 bConfigurationValue
6 iConfiguration
7 bmAttributes
8 MaxPower
Description
Length of this Descriptor = 9 bytes
Descriptor Type = Configuration
Total Length (L) Including Interface and Endpoint Descriptors
Total Length (H)
Number of Interfaces in this Configuration
Configuration Value Used by Set_Configuration Request to
Select this Configuration
Index of String Describing this Configuration = None
Attributes - Bus-Powered, No Wakeup
Maximum Power - 100 mA
Value
09H
02H
DAH
00H
01H
01H
00H
80H
32H
The configuration descriptor includes a total length field (offset 2-3) that encompasses all
interface and endpoint descriptors that follow the configuration descriptor. This configu-
ration describes a single interface (offset 4). The host selects this configuration by issuing
a Set_Configuration requests specifying configuration #1 (offset 5).
Table 5-11. USB Default Interface 0, Alternate Setting 0 Descriptor
Offset
Field
0 bLength
1 bDescriptorType
2 bInterfaceNumber
3 bAlternateSetting
4 bNumEndpoints
5 bInterfaceClass
6 bInterfaceSubClass
7 bInterfaceProtocol
8 iInterface
Description
Length of the Interface Descriptor
Descriptor Type = Interface
Zero-based Index of this Interface = 0
Alternate Setting Value = 0
Number of Endpoints in this Interface (Not Counting EPO) = 0
Interface Class = Vendor Specific
Interface Sub-class = Vendor Specific
Interface Protocol = Vendor Specific
Index to String Descriptor for this Interface = None
Value
09H
04H
00H
00H
00H
FFH
FFH
FFH
00H
Interface 0, alternate setting 0 describes endpoint 0 only. This is a zero bandwidth setting.
The interface has no string index.
Page 5-14
Chapter 5. EZ-USB CPU
EZ-USB TRM v1.9