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NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 725 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
EHCI Structural Parameters Register (EHCSPR)
Register
Offset
R/W
Description
Reset Value
EHCSPR
0x004
R
EHCI Structural Parameters Register
0x0000_0012
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
N_CC
N_PCC
7
6
5
4
3
2
1
0
Reserved
PPC
N_PORTS
Bits
Description
[31:16]
Reserved
Reserved.
[15:12]
N_CC
Number of Companion Controller
This field indicates the number of companion controllers associated with this USB 2.0 host
controller.
A zero in this field indicates there are no companion host controllers. Port-ownership hand-
off is not supported. Only high-speed devices are supported on the host controller root
ports.
A value larger than zero in this field indicates there are companion USB 1.1 host
controller(s). Port-ownership hand-offs are supported. High, Full- and Low-speed devices
are supported on the host controller root ports.
[11:8]
N_PCC
Number of Ports Per Companion Controller
This field indicates the number of ports supported per companion host controller. It is used
to indicate the port routing configuration to system software.
For example, if N_PORTS has a value of 6 and N_CC has a value of 2 then N_PCC could
have a value of 3. The convention is that the first N_PCC ports are assumed to be routed
to companion controller 1, the next N_PCC ports to companion controller 2, etc. In the
previous example, the N_PCC could have been 4, where the first 4 are routed to
companion controller 1 and the last two are routed to companion controller 2.
The number in this field must be consistent with N_PORTS and N_CC.
[7:5]
Reserved
Reserved.
[4]
PPC
Port Power Control
This field indicates whether the host controller implementation includes port power control.
A one in this bit indicates the ports have port power switches. A zero in this bit indicates
the port do not have port power stitches. The value of this field affects the functionality of
the Port Power field in each port status and control register.
[3:0]
N_PORTS
Number of Physical Downstream Ports
This field specifies the number of physical downstream ports implemented on this host
controller. The value of this field determines how many port registers are addressable in
the Operational Register Space (see Table 2-8). Valid values are in the range of 1H to FH.
A zero in this field is undefined.