UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
615 of 1269
NXP Semiconductors
UM10503
Chapter 24: LPC43xx USB1 Host/Device controller
3
PEC
0
Port disable/enable change
For the root hub, this bit gets set to a one only when a port is disabled due
to disconnect on the port or due to the appropriate conditions existing at
the EOF2 point (See
Chapter 11 of the USB Specification
). Software clears
this by writing a one to it.
This bit is 0 if PP (Port Power bit) is 0,
0
R/WC
0
No change.
1
Port enabled/disabled status has changed.
4
OCA
Over-current active
This bit will automatically transition from 1 to 0 when the over-current
condition is removed.
0
RO
0
The port does not have an over-current condition.
1
The port has currently an over-current condition.
5
OCC
Over-current change
This bit gets set to one when there is a change to Over-current Active.
Software clears this bit by writing a one to this bit position.
0
R/WC
6
FPR
Force port resume
Software sets this bit to one to drive resume signaling. The Host Controller
sets this bit to one if a J-to-K transition is detected while the port is in the
Suspended state. When this bit transitions to a one because a J-to-K
transition is detected, the Port Change Detect bit in the USBSTS register is
also set to one. This bit will automatically change to zero after the resume
sequence is complete. This behavior is different from EHCI where the host
controller driver is required to set this bit to a zero after the resume duration
is timed in the driver.
Note that when the Host controller owns the port, the resume sequence
follows the defined sequence documented in the USB Specification
Revision 2.0. The resume signaling (Full-speed ‘K’) is driven on the port as
long as this bit remains a one. This bit will remain a one until the port has
switched to the high-speed idle. Writing a zero has no affect because the
port controller will time the resume operation clear the bit the port control
state switches to HS or FS idle.
This bit is 0 if PP (Port Power bit) is 0.
0
R/W
0
No resume (K-state) detected/driven on port.
1
Resume detected/driven on port.
Table 482. Port Status and Control register in host mode (PORTSC1_H - address 0x4000 7184) bit description
…continued
Bit
Symbol
Value
Description
Reset
value
Access