Table 5-19. USB Default Interface 0, Alternate Setting 2, Isochronous Endpoint Descriptors
Field Description
bLength Length of this Endpoint Descriptor
Offset
0
1
2
3
4
5
6
0
1
2
3
4
5
6
0
1
2
3
4
5
6
0
1
2
3
4
5
6
0
1
2
3
4
5
6
0
1
2
3
4
5
6
Value
07H
05H
88H
01H
10H
01H
01H
07H
05H
08H
01H
00H
10H
01H
07H
05H
89H
01H
10H
00H
01H
07H
05H
09H
01H
10H
00H
01H
07H
05H
8AH
01H
10H
00H
01H
07H
05H
0AH
01H
10H
00H
01H
bDescriptorType
bEndpointAddress
bmAttributes
Descriptor Type = Endpoint
Endpoint Direction (1 is in) and Address = IN8
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 256 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
Length of this Endpoint Descriptor
Descriptor Type = Endpoint
bLength
bDescriptorType
bEndpointAddress
bmAttributes
Endpoint Direction (1 is in) and Address = OUT8
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 256 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
Length of this Endpoint Descriptor
Descriptor Type = Endpoint
bLength
bDescriptorType
bEndpointAddress
bmAttributes
Endpoint Direction (1 is in) and Address = IN9
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 16 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
Length of this Endpoint Descriptor
Descriptor Type = Endpoint
bLength
bDescriptorType
bEndpointAddress
bmAttributes
Endpoint Direction (1 is in) and Address = OUT9
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 16 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
Length of this Endpoint Descriptor
Descriptor Type = Endpoint
bLength
bDescriptorType
bEndpointAddress
bmAttributes
Endpoint Direction (1 is in) and Address = IN10
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 16 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
Length of this Endpoint Descriptor
Descriptor Type = Endpoint
bLength
bDescriptorType
bEndpointAddress
bmAttributes
Endpoint Direction (1 is in) and Address = OUT10
XFR Type = ISO
wMaxPacketSize (L) Maximum Packet Size = 16 Bytes
wMaxPacketSize (H) Maximum Packet Size - High
bInterval
Polling Interval in Milliseconds (1 for iso)
The only differences between alternate settings 1 and 2 are the maximum packet sizes for
EP8IN and EP8OUT. This is a high-bandwidth setting using 256 bytes each.
EZ-USB TRM v1.9
Chapter 5. EZ-USB CPU
Page 5-21
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