Cirrus Logic EP93xx - Manual (Page 467)

DS785UM1 11-27
Copyright 2007 Cirrus Logic
Universal Serial Bus Host Controller
EP93xx User’s Guide
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0x8002_0040
Default:
0x0000_0000
Definition:
Defines the earliest time the host controller should start processing the
periodic list.
Bit Description:
RSVD: Reserved. Unknown During Read.
PS: PeriodicStart. After a hardware reset, this field is cleared.
This is then set by HCD during the HC initialization. The
value is calculated roughly as 10% off from HcFmInterval.
A typical value will be 0x03E67. When HcFmRemaining
reaches the value specified, processing of the periodic
lists will have priority over Control/Bulk processing. HC will
therefore start processing the Interrupt list after completing
the current Control or Bulk transaction that is in progress.
HcLSThreshold
Address:
0x8002_0044
Default:
0x0000_0628
Definition:
Contains a value used by the host controller to determine whether to commit
to the transfer of a maximum 8-byte LS packet before EOF.
Bit Description:
RSVD: Reserved. Unknown During Read.
LST: LSThreshold. This field contains a value which is
compared to the FrameRemaining field prior to initiating a
Low Speed transaction. The transaction is started only if
FrameRemaining >= this field. The value is calculated by
HCD with the consideration of transmission and setup
overhead.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RSVD
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD LST