Cirrus Logic EP93xx - Manual (Page 465)

DS785UM1 11-25
Copyright 2007 Cirrus Logic
Universal Serial Bus Host Controller
EP93xx User’s Guide
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RSVD: Reserved. Unknown During Read.
FI: FrameInterval. This specifies the interval between two
consecutive SOFs in bit times. The nominal value is set to
be 11,999. HCD should store the current value of this field
before resetting HC. By setting the HostControllerReset
field of HcCommandStatus as this will cause the HC to
reset this field to its nominal value. HCD may choose to
restore the stored value upon the completion of the Reset
sequence.
FSMPS: FSLargestDataPacket. This field specifies a value which is
loaded into the Largest Data Packet Counter at the
beginning of each frame. The counter value represents the
largest amount of data in bits which can be sent or
received by the HC in a single transaction at any given
time without causing scheduling overrun. The field value is
calculated by the HCD.
FIT: FrameIntervalToggle. HCD toggles this bit whenever it
loads a new value to FrameInterval.
HcFmRemaining
Address:
0x8002_0038
Default:
0x0000_0000
Definition:
Contains the time remaining in the current frame.
Bit Descriptions:
RSVD: Reserved. Unknown During Read.
FR: 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 USBOPERATIONAL
state, HC re-loads the content with the FrameInterval of
HcFmInterval and uses the updated value from the next
SOF.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
FRT RSVD
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD FR