Allwinner A20 - Page 683

A20 User Manual (Revision 1.2) Copyright © 2013 Allwinner Technology Co., Ltd. All Rights Reserved. Page 683 / 812
6
R/W
R/W
0x0
RootHubStatusChange
This bit is set when the content of HcRhStatus or the content of
any of HcRhPortStatus[NumberofDownstreamPort] has
changed.
5
R/W
R/W
0x0
FrameNumberOverflow
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.
4
R/W
R/W
0x0
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.
3
R/W
R/W
0x0
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 USBRseume state.
2
R/W
R/W
0x0
StartofFrame
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.
1
R/W
R/W
0x0
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.
0
R/W
R/W
0x0
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.
6.8.7.5. HCINTERRUPTENABLE REGISTER
Offset: 0x410
Register Name: HcInterruptEnable Register
Default Value: 0x0
Bit
Read/Write
Default
Description
HCD
HC
31:7
Reserved
6
R/W
R
0x0
RootHubStatusChange Interrupt Enable
0
Ignore;
1
Enable interrupt generation due to Root Hub Status
Change;
5
R/W
R
0x0
FrameNumberOverflow Interrupt Enable
0
Ignore;
1
Enable interrupt generation due to Frame Number Over
Flow;
UnrecoverableError Interrupt Enable