Owners manual

Interfaces
H3 Datasheet(Revision1.2) Copyright© 2015 Allwinner Technology Co.,Ltd.All Rights Reserved. Page 505
11b
USBSuspend
A transition to USBOperational from another state causes SOF generation
to begin 1 ms later. HCD may determine whether HC has begun sending
SOFs by reading the StartoFrame field of
HcInterruptStatus.
This field may be changed by HC only when in the USBSUSPEND state. HC
may move from the USBSUSPEND state to the USBRESUME state after
detecting the resume signaling from a downstream port.
HC enters USBSUSPEND after a software reset, whereas it enters
USBRESET after a hardware reset. The latter also resets the Root
Hub and asserts subsequent reset signaling to downstream ports.
5
R/W
R
0x0
BulkListEnable
This bit is set to enable the processing of the Bulk list in the next
Frame. If cleared by HCD, processing of the Bulk list does not occur after
the next SOF. HC checks this bit whenever it determines to process the list.
When disabled, HCD may modify the list. If HcBulkCurrentED is pointing to
an ED to be removed, HCD must advance the pointer by updating
HcBulkCurrentED before re-enabling processing of the list.
4
R/W
R
0x0
ControlListEnable
This bit is set to enable the processing of the Control list in the next Frame.
If cleared by HCD, processing of the Control list does not occur after the
next SOF. HC must check this bit whenever it determines to process the list.
When disabled, HCD may modify the list. If HcControlCurrentED is pointing
to an ED to be removed, HCD must advance the pointer by updating
HcControlCurrentED before re-enabling processing of the list.
3
R/W
R
0x0
IsochronousEnable
This bit is used by HCD to enable/disable processing of isochronous EDs.
While processing the periodic list in a Frame, HC checks the status of this
bit when it finds an Isochronous ED (F=1). If set (enabled), HC continues
processing the EDs. If cleared (disabled), HC halts processing of the periodic
list (which now contains only isochronous EDs) and begins processing the
Bulk/Control lists.
Setting this bit is guaranteed to take effect in the next Frame (not the
current Frame).
2
R/W
R
0x0
PeriodicListEnable
This bit is set to enable the processing of periodic list in the next Frame. If
cleared by HCD, processing of the periodic list does not occur after the next
SOF. HC must check this bit before it starts processing the list.
1:0
R/W
R
0x0
ControlBulkServiceRatio
This specifies the service ratio between Control and Bulk EDs. Before
processing any of the nonperiodic lists, HC must compare the ratio
specified with its internal count on how many nonempty Control EDs have
been processed, in determining whether to continue serving another
Control ED or switching to Bulk EDs. The internal count will be retained
when crossing the frame boundary. In case of reset, HCD is responsible for
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