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ADM5120
Register Description
4.6.8 SOF Frame number, offset 0x1C
Bits
Type Name
Description
Initial value
15:0 R/W
FM_NUM
Frame number
This field is a 16-bit counter. It provides a timing
reference among events happening in the Host
Controller and the Host Controller Driver. The Host
Controller Driver may use the 16-bit value specified in
this register and generate a 32-bit frame number without
requiring frequent access to the register.
0
29:16 R/W FM_REMAININ
G
FrameRemaining
This counter is decremented at each bit time. When it
reaches zero, it is reset by loading the frame Interval
value specified in FM_INTERVAL at the next bit time
boundary. When entering the
USBOPERATIONAL state, HC re-loads the content
with the FM_INTERVAL of and uses the updated value
from the next SOF.
0
30 RO
Reserved
Not
Applicable
0
31 R/W
FM_REMAININ
G_TOG
FrameRemaining toggle
This bit is loaded from the FM_INTERVAL_TOG field
of FM_INTERVAL whenever FM_REMAIN remaining
reaches 0. This bit is used by software for the
synchronization between FM_INTERVAL
and FM_REMAIN.
0
4.6.9 Reserved, offset 0x20 – 0x6C
Bits
Type Name
Description
Initial value
31:0
Reserved
Not
Applicable
4.6.10 Low speed threshold, offset 0x70
Bits
Type Name
Description
Initial value
11:0 R
LS_THRES
Low Speed Threshold
This field contains a value which is compared to the
FM_REMAIN field prior to initiating a Low Speed
transaction. The transaction is started only if
FM_REMAIN >= this field. The value is calculated by
HCD with the consideration of transmission and setup
overhead.
0628h
31:12 RO Reserved
Reserved
0
ADMtek Inc.
4-30