Хост-контроллер USB2.0: список регистров

  Unused

  ROOT_HUB_STATUS_CHANGE

This bit is set when the content of HcRhStatus or the content of any of
HcRhPortStatus[NumberofDownstreamPort] has changed.

  FRAME_NUMBER_OVERFLOW

This bit is set when the MSb of HcFmNumber (bit 15) changes value, from 0 to 1 or from 1 to 0, and after HccaFrameNumber has been updated.

  UN_RECOVERABLE_ERROR

This bit is set when HC detects a system error not related to USB.
HC should not proceed with any processing nor signaling before the system error has been corrected.
HCD clears this bit after HC has been reset.

  RESUME_DETECTED

This bit is set when HC detects that a device on the USB is asserting resume signaling.
It is the transition from no resume signaling to resume signaling causing this bit to be set.
This bit is not set when HCD sets the USB Resume state.

  START_OF_FRAME

This bit is set by HC at each start of frame and after the update of
HccaFrameNumber. HC also generates a SOF token at the same time.

  WRITE_BACK_DONE_HEAD

This bit is set immediately after HC has written HcDoneHead to HccaDoneHead.
Further updates of the HccaDoneHead will not occur until this bit has been cleared.
HCD should only clear this bit after it has saved the content of HccaDoneHead.

  SCHEDULING_OVERRUN

This bit is set when the USB schedule for the current Frame overruns and after the update of HccaFrameNumber.
A scheduling overrun will also cause the SchedulingOverrunCount of HcCommandStatus to be incremented.

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  o_hcinterruptstatus
{
  struct
  {
   unsigned scheduling_overrun : 1;
   unsigned write_back_done_head : 1;
   unsigned start_of_frame : 1;
   unsigned resume_detected : 1;
   unsigned un_recoverable_error : 1;
   unsigned frame_number_overflow : 1;
   unsigned root_hub_status_change : 1;
   unsigned unused0 : 25;
  } b;
   unsigned long w;
} O_HcInterruptStatus