Information

Universal Serial Bus Interface
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
Freescale Semiconductor 13-29
4 OCA Over-current active. This bit will automatically transition from one to zero when the over current condition is
removed.
Host/OTG mode:
• The user can provide over-current detection to the USBn_PWRFAULT signal for this condition.
Device mode:
• This bit must always be 0.
1 Port currently in over-current condition.
0 Port not in over-current condition.
3 PEC Port enable/disable change.
For the root hub, this bit gets set 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.[
In device mode:
• The device port is always enabled. (This bit is zero.)
1 Port disabled.
0 No change.
This field is zero if Port Power(PP) is zero.
2 PE Port enabled/disabled.
Host mode:
• Ports can only be enabled by the controller as a part of the reset and enable. Software cannot enable a port
by writing a one to this field. Ports can be disabled by either a fault condition (disconnect event or other fault
condition) or by the host software. Note that the bit status does not change until the port state actually
changes. There may be a delay in disabling or enabling a port due to other host and bus events.
• When the port is disabled, (0) downstream propagation of data is blocked except for reset.
• This field is zero if Port Power(PP) is zero in host mode.
Device mode:
• The device port is always enabled. (This bit is one.)
1 CSC Connect change status.
Host mode:
• This bit indicates a change has occurred in the port’s Current Connect Status. the controller sets this bit for
all changes to the port device connect status, even if system software has not cleared an existing connect
status change. For example, the insertion status changes twice before system software has cleared the
changed condition, hub hardware is ‘setting’ an already-set bit (i.e., the bit will remain set). Software clears
this bit by writing a one to it.
1 Connect Status has changed.
0 No change.
• This field is zero if Port Power(PP) is zero.
Device mode:
• This bit is undefined.
0 CCS Current connect status.
Host mode:
1 Device is present
0 No device present.
This field is zero if Port Power(PP) is zero in host mode.
In device mode:
1Attached
0 Not attached.
A one indicates that the device successfully attached and is operating in either high-speed or full-speed as
indicated by the High Speed Port bit in this register. A zero indicates that the device did not attach successfully
or was forcibly disconnected by the software writing a zero to USBCMD[RS] (run bit). It does not state the
device being disconnected or suspended.
Table 13-23. PORTSC Register Field Descriptions (continued)
Bits Name Description