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M451
May. 4, 2018
Page
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1006
Rev.2.08
M4
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Host Controller Root Hub Descriptor A Register (HcRhDescriptorA)
Register
Offset
R/W
Description
Reset Value
HCRHDESCRIP
TORA
0x048 R/W
Host Controller Root Hub Descriptor A Register
0x0000_0902
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
NOCP
OCPM
Reserved
PSM
7
6
5
4
3
2
1
0
NDP
Bits
Description
[31:13]
Reserved
Reserved.
[12]
NOCP
No over Current Protection
This bit describes how the over current status for the Root Hub ports reported.
0 = Over current status is reported.
1 = Over current status is not reported.
[11]
OCPM
over Current Protection Mode
This bit describes how the over current status for the Root Hub ports reported. This bit is
only valid when NOCP (HcRhDescriptorA[12]) is cleared.
0 = Global Over current.
1 = Individual Over current.
[10:9]
Reserved
Reserved.
[8]
PSM
Power Switching Mode
This bit is used to specify how the power switching of the Root Hub ports is controlled.
0 = Global Switching.
1 = Individual Switching.
[7:0]
NDP
Number Downstream Ports
USB host control supports two downstream ports and only one port is available in this
series of chip.