Cirrus Logic EP93xx - Manual (Page 469)

DS785UM1 11-29
Copyright 2007 Cirrus Logic
Universal Serial Bus Host Controller
EP93xx User’s Guide
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NPS: NoPowerSwitching. These bits are used to specify
whether power switching is supported or port are always
powered. It is implementation-specific. When this bit is
cleared, the PowerSwitchingMode specifies global or per-
port switching.
0: Ports are power switched
1: Ports are always powered on when the HC is powered
on.
DT: DeviceType. This bit specifies that the Root Hub is not a
compound device. The Root Hub is not permitted to be a
compound device. This field should always read/write 0.
OCPM: OverCurrentProtectionMode. This bit describes how the
overcurrent status for the Root Hub ports are reported. At
reset, this fields should reflect the same mode as
PowerSwitchingMode. This field is valid only if the
NoOverCurrentProtection field is cleared.
0: Over-current status is reported collectively for all
downstream ports
1: Over-current status is reported on a per-port basis.
NOCP: NoOverCurrentProtection. This bit describes how the
overcurrent status for the Root Hub ports are reported.
When this bit is cleared, the OverCurrentProtectionMode
field specifies global or per-port reporting.
0: Over-current status is reported collectively for all
downstream ports
1: No overcurrent protection supported
P: PowerOnToPowerGoodTime. This byte specifies the
duration HCD has to wait 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 P[7:0] * 2 ms.
0x05 = 10 ms
HcRhDescriptorB
Address:
0x8002_004C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RSVD PPCM
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD DR