ACS8520T Semtech, ACS8520T Datasheet - Page 91

• Manufacturer Part Number: ACS8520T
• Description: Synchronous Equipment Timing Source (SETS) for Stratum 3/4E/4 and SMC Systems
• Manufacturer: Semtech

Address (hex):
Revision 3.02/October 2005 © Semtech Corp.
ADVANCED COMMUNICATIONS
Register Name
auto_averaging fast_averaging
Bit No.
Bit 7
[4:3]
[2:0]
5
40 (cont...)
cnfg_holdover_modes
Description
read_average
Bit to control whether the value read from the
holdover_frequency_value register is the value
written to that register, or the averaged Holdover
frequency. This allows software to use the internal
averager as part of the Holdover algorithm, but use
manual Holdover mode plus software to enhance
the performance.
mini_holdover_mode
Mini-holdover is a term used to describe the state of
the DPLL when it is in locked mode, but it has
temporarily lost its input. This may be a temporary
state, or last for many seconds whilst an input is
checked for inactivity. The DPLL behaves exactly as
in Holdover, and the frequency can be determined
in the same selection of ways (instantaneously, fast
averaged or slow averaged).
holdover_frequency_value [18:16]
Bit 6
read_average
Bit 5
Description
Bit 4
mini_holdover_mode
FINAL
Page 91
(R/W) Register to control the
Holdover modes of the T0 DPLL.
Bit Value
Bit 3
00
01
10
11
0
1
-
Value Description
Value read from holdover_frequency_value is the
value written to it.
Value read from a holdover_frequency_value is
either the fast or slow averaged frequency as
determined by fast_averaging.
Mini-holdover frequency determined in the same
way as for full Holdover mode.
Mini-holdover frequency frozen instantaneously.
Mini-holdover frequency taken from fast averager.
Mini-holdover frequency taken from slow averager.
See Reg. 3F (cnfg_holdover_frequency) for details.
Bit 2
holdover_frequency_value [18:16]
Default Value
ACS8520 SETS
Bit 1
DATASHEET
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1000 1000
Bit 0