SH7760 Datasheet, PDF (790/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

21.3.19 Root Hub Descriptor A Register (HcRhDescriptorA)
HcRhDescriptorA is the first register of two describing the characteristics of the root hub. The
descriptor length (11), descriptor type (TBD), and hub controller current (0) bits in the hub Class
Descriptor are emulated by HCD. All other bits are allocated in HcRhDescriptorA and
HcRhDescriptorB.
Bit: 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
POTPGT
-
-
-
-
-
-
-
-
Initial value: 0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
R/W: R/W R/W R/W R/W R/W R/W R/W R/W R
R
R
R
R
R
R
R
Bit: 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
-
-
- NOCP OCPM DT NPS PSM
NDP
Initial value: 0
0
0
1
0
0
1
0
0
0
0
0
0
0
1
0
R/W: R
R
R R/W R/W R R/W R/W R
R
R
R
R
R
R
R
Bit
Bit Name Initial Value R/W Description
31 to 24 POTPGT H’02
R/W Power On To Power Good Time
This bit specifies the HCD wait time before
accessing a powered-on port of the root hub. It is
implementation-specific. The unit of time is 2 ms.
The duration is calculated as POTPGT × 2 ms.
23 to 13 
All 0
R
Reserved
These bits are always read as 0. Always write 0 to
this bit.
12
NOCP
1
R/W No Overcurrent Protection
This bit describes the overcurrent condition
reporting method for root hub ports. When this bit is
cleared to 0, the OCPM bit specifies either global or
per-port reporting.
0: Overcurrent status info is collected
1: Overcurrent protection is not supported
Note: There are restrictions on this bit. For details,
see section 21.6, Restrictions on
HcRhDescriptorA.
Rev. 1.0, 02/03, page 740 of 1294