
USB on-the-go full-speed (OTG_FS)
RM0351
1686/1830
DocID024597 Rev 5
Bit 8
PRST:
Port reset
When the application sets this bit, a reset sequence is started on this port. The application
must time the reset period and clear this bit after the reset sequence is complete.
0: Port not in reset
1: Port in reset
The application must leave this bit set for a minimum duration of at least 10 ms to start a
reset on the port. The application can leave it set for another 10 ms in addition to the
required minimum duration, before clearing the bit, even though there is no maximum limit
set by the USB standard.
High speed: 50 ms
Full speed/Low speed: 10 ms
Bit 7
PSUSP:
Port suspend
The application sets this bit to put this port in Suspend mode. The core only stops sending
SOFs when this is set. To stop the PHY clock, the application must set the Port clock stop
bit, which asserts the suspend input pin of the PHY.
The read value of this bit reflects the current suspend status of the port. This bit is cleared
by the core after a remote wakeup signal is detected or the application sets the Port reset bit
or Port resume bit in this register or the Resume/remote wakeup detected interrupt bit or
Disconnect detected interrupt bit in the Core interrupt register (WKUINT or DISCINT in
OTG_GINTSTS, respectively).
0: Port not in Suspend mode
1: Port in Suspend mode
Bit 6
PRES:
Port resume
The application sets this bit to drive resume signaling on the port. The core continues to
drive the resume signal until the application clears this bit.
If the core detects a USB remote wakeup sequence, as indicated by the Port
resume/remote wakeup detected interrupt bit of the Core interrupt register (WKUINT bit in
OTG_GINTSTS), the core starts driving resume signaling without application intervention
and clears this bit when it detects a disconnect condition. The read value of this bit indicates
whether the core is currently driving resume signaling.
0: No resume driven
1: Resume driven
When LPM is enabled and the core is in L1 state, the behavior of this bit is as follow:
1. The application sets this bit to drive resume signaling on the port.
2. The core continues to drive the resume signal until a predetermined time specified in
BESLTHRS[3:0] field of OTG_GLPMCFG register.
3. If the core detects a USB remote wakeup sequence, as indicated by the Port
L1Resume/Remote L1Wakeup Detected Interrupt bit of the core Interrupt register
(WKUPINT in OTG_GINTSTS), the core starts driving resume signaling without application
intervention and clears this bit at the end of resume.This bit can be set or cleared by both
the core and the application. This bit is cleared by the core even if there is no device
connected to the host.
Bit 5
POCCHNG:
Port overcurrent change
The core sets this bit when the status of the Port overcurrent active bit (bit 4) in this register
changes.
Bit 4
POCA:
Port overcurrent active
Indicates the overcurrent condition of the port.
0: No overcurrent condition
1: Overcurrent condition
Bit 3
PENCHNG:
Port enable/disable change
The core sets this bit when the status of the Port enable bit 2 in this register changes.