HS_USB2.0 host
RM0082
438/844
Doc ID 018672 Rev 1
[06]
FPR
1’h0
Force port resume.
This bit states whether the port is in suspend, according to
encoding:
1‘b0 = No resume (K-state) detected/driven on port.
1‘b1 = Resume detected/driven on port.
The functionality defined for manipulating this bit depends on
the value of the suspend bit (see above). For example, if the
port is not suspended (S is 1‘b0 and PEN is 1‘b1) and
software transitions this bit to 1‘b1, then the effects on the bus
are undefined.
The EHCI host controller sets the FPR bit to 1‘b1 if a J-to-K
transition is detected while the port is in the Suspend state.
When this bit changes to 1‘b1 because a J-to-K transition is
detected, the port change detect (PCD) bit in the USBSTS
register is also set to 1‘b1.
Software sets this bit to 1‘b1 to drive resume signaling. In this
case, the EHCI host controller must not set the port change
detect bit. The resume signaling (full-speed 'K') is driven on
the port as long as this bit remains a 1‘b1. Software must
appropriately time the resume and set this bit to a zero when
the appropriate amount of time has elapsed. Writing a zero
(from one) causes the port to return to high-speed mode
(forcing the bus below the port into a high-speed idle). This bit
will remain a one until the port has switched to the high-speed
idle.
The EHCI host controller must complete this transition within 2
milliseconds of software setting this bit to 1‘b0.
Note: This field is zero if port power (PP bit in this register) is
zero.
[05]
OcC
1’h0
Over-current change.
This bit is set to 1‘b1 when there is a change in the over-
current active (OcA) bit in this register. Software clears this bit
by writing a one to this bit position.
[04]
OcA
1’h0
Over-current active.
This bit states whether the port has a over-current condition,
according to encoding:
1‘b0 = This port does not have an over-current condition.
1‘b1 = This port currently has an over-current condition.
Note: This bit will automatically transition from a 1‘b1 to a 1‘b0
when the over-current condition is removed.
[03]
PEDC
1’h0
Port enable/disable change.
This bit is set to 1‘b1 when port enabled/disabled status
(reflected by the PEN bit in this register) has changed.
Software clears this bit by writing a one to this bit position.
Table 362.
PORTSC register bit assignments (continued)
Bit
Name
Reset
value
Description