Digi NS9750 - Manual (Page 778)

U S B h o s t b l o c k r e g i s t e r s
7 5 4 N S 9 7 5 0 H a r d w a r e R e f e r e n c e
D11 R/W OCPM IS OverCurrentProtectionMode
Describes how the overcurrent status for the root hub ports
is reported. At reset, this field should reflect the same
mode as PowerSwitchingMode (D08 in this register). The
OCPM field is valid only if the NoOverCurrentProtection
field (D12 in this register) is cleared.
0 Overcurrent status is reported collectively for all
downstream ports.
1 Overcurrent status is reported on a per-port basis.
D10 R DT 0b Device type
Specifies that the root hub is not a compound device. The
root hub is not allowed to be a compound device.
This field should always read 0.
D09 R/W PSM IS PowerSwitchingMode
Specifies how the power switching of the root hubs is
controlled. This field is valid only if the
NoPowerSwitching field (D08 in this register) is cleared.
0 All ports are powered at the same time.
1 Each port is powered individually. This mode allows
port power to be controlled by either the global switch
or per-port switching. If the PortPowerControlMask
bit (see "HcRhDescriptorB register" on page 755) is
set, the port responds only to port power commands
(Set/ClearPortPower). If the port mask is cleared, the
port is controlled only by the global power switch
(Set/ClearGlobalPower).
D08 R/W NPS IS NoPowerSwitching
Specifies whether power switching is supported or ports
are always powered. When this bit is cleared, the
PowerSwitchingMode (D09 in this register) specifies
global or per-port switching.
0 Ports are power switched.
1 Ports are always powered on when the host controller
is powered on.
D07:00 R NDP IS NumberDownstreamPorts
Specifies the number of downstream ports supported by
the root hub. The minimum number of ports is 1; the
maximum number of ports supported is 15.
Bits Access Mnemonic Reset Description
Table 441: HcRhDescriptorA register