Cirrus Logic EP93xx User Manual

Page 457

DS785UM1

11-17

Universal Serial Bus Host Controller

EP93xx User’s Guide

HcInterruptStatus

Address:

0x8002_000C

Default:

0x0000_0000

Definition:

Provides interrupt status information.

Bit Descriptions:

RSVD:

Reserved. Unknown During Read.

SO:

SchedulingOverrun. 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.

WDH:

WritebackDoneHead. 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.

SF:

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

RD:

ResumeDetected. 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 USBRESUME state.

UE:

UnrecoverableError. 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.

RSVD

RHSC

FNO

WDH