Table 5-12. USB Default Interface 0, Alternate Setting 1 Descriptor
Field Description
bLength Length of the Interface Descriptor
Offset
Value
09H
04H
00H
01H
0
1
2
3
4
5
6
7
8
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
Descriptor Type = Interface
Zero-based Index of this Interface = 0
Alternate Setting Value = 1
Number of Endpoints in this Interface (Not Counting EPO) = 13 0DH
Interface Class = Vendor Specific
FFH
FFH
FFH
00H
bInterfaceSubClass Interface Sub-class = Vendor Specific
bInterfaceProtocol
iInterface
Interface Protocol = Vendor Specific
Index to String Descriptor for this Interface = None
Interface 0, alternate setting 1 has thirteen endpoints, whose individual descriptors follow
the interface descriptor. The alternate settings have no string indices.
Table 5-13. USB Default Interface 0, Alternate Setting 1, Interrupt Endpoint Descriptor
Offset
Field
bLength
Description
Length of this Endpoint Descriptor
Value
07H
05H
81H
03H
10H
00H
0AH
0
1
2
3
4
5
6
bDescriptorType
bEndpointAddress
bmAttributes
Descriptor Type = Endpoint
Endpoint Direction (1 is in) and Address = IN1
XFR Type = INT
wMaxPacketSize (L) Maximum Packet Size = 16 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds = 10 ms
Interface 0, alternate setting 1 has one interrupt endpoint, IN1, which has a maximum
packet size of 16 and a polling interval of 10 ms.
EZ-USB TRM v1.9
Chapter 5. EZ-USB CPU
Page 5-15
CYPRESS [ CYPRESS ]
