AMD SB600 Technical Reference Manual page 60

Field Name Bits
FR 13:0
Reserved 30:14
FRT 31
Field Name Bits
FN 15:0
Reserved 31:16
Field Name Bits
PS 13:0
Reserved 31:14
Field Name Bits
LST 11:0
Reserved 31:12
©2008 Advanced Micro Devices, Inc.
AMD SB600 Register Reference Manual
HcFmRemaining - 32 bits - [MEM_Reg : 38h]
Default HCD HC
0000h R RW
0b R RW
HcFmNumber - 32 bits - [MEM_Reg : 3Ch]
Default HCD HC
0000h R RW
HcPeriodicStart - 32 bits - [MEM_Reg : 40h]
Default HCD HC
0000h RW R
HcLSThreshold - 32 bits - [MEM_Reg : 44h]
Default HCD HC
0628h RW R
Description
FrameRemaining
This counter is decremented at each bit time. When it
reaches zero, it is reset by loading the FrameInterval
value specified in HcFmInterval at the next bit time
boundary. When entering the
state, HC re-loads the content with the
FrameInterval of HcFmInterval and uses the updated
value from the next SOF.
Reserved
FrameRemainingToggle
This bit is loaded from the FrameIntervalToggle field
of HcFmInterval whenever FrameRemaining
reaches 0. This bit is used by HCD for the
synchronization between FrameInterval and
FrameRemaining.
Description
This is incremented when HcFmRemaining is re-
loaded. It will be rolled over to 0h after ffffh. When
entering the B
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incremented automatically. The content will be written
to HCCA after HC has incremented the
FrameNumber at each frame boundary and sent a
SOF but before HC reads the first ED in that Frame.
After writing to HCCA, HC will set the
StartofFrame in HcInterruptStatus.
Reserved
Description
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 3E67h. 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.
Reserved
Description
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  t his field. The value is calculated
by HCD with the consideration of transmission and
setup overhead.
Reserved
OCHI USB 1.1 and EHCI USB 2.0 Controllers
Proprietary
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state, this will be
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