MCIMX27 Datasheet, PDF (998/1650 Pages) Freescale Semiconductor, Inc – Multimedia Applications Processor

High-Speed USB On-The-Go (HS USB-OTG)
detecting activity on the USB line. The wake-up logic can optionally wake the CPU when it is in sleep
mode at the time of the request. The power control mechanism is described in the VUSB-HS-SPH and
VUSB-HS-OTG reference manuals. For details on the power control module, refer to the Power Module
creation guide.
30.6.4.1 Entering Suspend Mode
Suspend mode is always entered under control of driver software by setting the appropriate bit INT
PORTSC register. Once the controller is suspended, the clocks to the USB block can be stopped.
30.6.4.2 Wake-up Events
The power control module monitors the USB bus when the USB core is in the suspend state. Depending
on whether the core is on Host or Device mode, a number of wakeup conditions are detected. Upon
detection of a wakeup condition, an interrupt (asynchronous) is generated on the CPU complex. This
interrupt will also re-activate the clocks if these were stopped during the suspend.
30.6.4.2.1 Host Mode Events
The Host controller wakes-up on the following events:
Remote Wakeup Request
A peripheral can request the host to re-activate the bus by driving wake-up signaling on the Dm/Dp lines.
The power control module will detect a J-K transition on the Dm/Dp lines and signal the wakeup request
to the core.
Wake on Over-Current
If wake on overcurrent is enabled in the PORTSC registers, the power control module will signal a wakeup
condition to the USB core.
Wake on Disconnect
The Power Control module detects disconnect events by monitoring the Dp/Dm lines. When a disconnect
event is detected (Dm = Dp = 0) and the Wake on Disconnect is enabled in the PORTSC register, the core
will be notified.
Wake on Connect
Similar to the Wake on Disconnect, the power control module detects a connect event (Dm or Dp High)
and signals this to the USB core by setting the pwrctl_wakeup signal if enabled in the PORTSC register.
30.6.4.2.2 Device mode events
When the OTG controller is configured for peripheral operation, the power control module will detected
following events:
30-16
MCIMX27 Multimedia Applications Processor Reference Manual, Rev. 0.2
Freescale Semiconductor