CX82100 Home Network Processor Data Sheet
8.3.2
Example of Endpoint Buffer Encoding
As shown in Figure 8-4, the HNP supports one configuration, one interface with no
alternate setting and four logical endpoints (Endpoints 1, 2, 3, and 4). The first three
endpoints are bidirectional endpoints and the fourth is an interrupt endpoint, therefore
there are nine physical endpoints total (including controlled Endpoint 0). In the UDC, one
EndPtBuf (Endpoint Buffer) is associated with each physical endpoint. Hence, there are
eight EndPtBufs in the UDC for the configuration shown in Figure 8-4. Endpoint 0 needs
only one EndPtBuf, although it is bidirectional.
An example of the encoding of the EndPtBuf is shown in Table 8-2. Except for interrupt
endpoint’s packet size being fixed at 8 bytes, other endpoints’ packet size must be less
than or equal to 64 bytes.
Figure 8-4. Example of an USB Device for HNP
Configuration
Interface 0
1
Alt Setting
0
EP 0
1
EP 1
2
EP 1
3
EP 2
4
EP 2
5
EP 3
6
EP 3
7
EP 4
8
Logical No.
Physical No.
Control
Bulk-IN
Bulk-OUT
Bulk-IN
Bulk-OUT
Bulk-IN
Bulk-OUT
Interrupt
101545_057
Table 8-2. Example of the EndPtBuf Encoding
EndPtBuf No.
39:36
0000
0001
0001
0010
0010
0011
0011
0100
35:34
01
01
01
01
01
01
01
01
33:32
00
00
00
00
00
00
00
00
31:29
28:27
00
10
10
10
10
10
10
11
26
0
0
1
0
1
0
1
1
25:16
15:0
1
2
3
4
5
6
7
8
000
000
000
000
000
000
000
000
00 0100 0000
00 0100 0000
00 0100 0000
00 0100 0000
00 0100 0000
00 0100 0000
00 0100 0000
00 0001 0100
0000 0000 0000 0000
0000 0000 0000 0001
0000 0000 0000 0001
0000 0000 0000 0001
0000 0000 0000 0010
0000 0000 0000 0011
0000 0000 0000 0011
0000 0000 0000 0100
101306C
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