ACS8509 Semtech Corporation, ACS8509 Datasheet - Page 33

• Manufacturer Part Number: ACS8509
• Description: Synchronous Equipment Timing Source for Sonet or SDH Network Elements
• Manufacturer: Semtech Corporation

Table 14 Register Description (cont...)
Revision 2.00/January 2006 © Semtech Corp.
ADVANCED COMMUNICATIONS
3E
3F
40
41
42
43
44
45
Addr.
(Hex)
cnfg_holdover_offset
cnfg_freq_limit
cnfg_interrupt_mask
Register Name
This register holds a 19-bit signed integer, representing the holdover offset value,
which can be used to set the holdover mode frequency when enabled via the
holdover offset enabled bit in the cnfg_mode register.
Bits (7:0) cnfg_holdover_offset bits (7:0).
Bits (7:0) cnfg_holdover_offset bits (15:8).
Bit 7
=1 Auto Holdover Averaging enable. This enables the frequency average to be taken
from 32 samples. One sample taken every 32 seconds, after the frequency has been
confirmed to be in-band by the frequency monitors. This gives a 17 minute history of
the currently locked to reference source for use in Holdover. (default).
=0 Auto Holdover Averaging disabled.
Bits (6:3) Unused.
Bits (2:0) cnfg_holdover_offset bits (18:16).
This register holds a 10 bit unsigned integer representing the pull-in range of the
DPLL. It should be set according to the accuracy of crystal implemented in the
application, using the following formula:
Default value is ±9.3 ppm.
Bits (7:0) cnfg_freq_limit bits (7:0).
Bits (7:2) Unused.
Bits (1:0) cnfg_freq_limit bits (9:8).
Each bit, if set to 0 will disable the appropriate interrupt source in either the interrupt
status register or the sts_T4_inputs register.
Bit 7
Bit 6
Bits (5:0) Set to 0.
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bits (1:0) Set to 0.
Bits (7:5) Set to 0.
Bit 4
Bits (3:0) Set to 0.
Frequency range ±(ppm) = (cnfg_freq_limit x 0.0785)+0.01647 or
cnfg_freq_limit = (Frequency range ± (ppm) - 0.01647) / 0.0785.
cnfg_interrupt_mask bits (7:0):
cnfg_interrupt_mask bits (15:8):
cnfg_interrupt_mask bits (20:16):
SEC2.
SEC1.
Operating mode.
Main Ref failed.
Set to 0.
SEC4.
Set to 0.
SEC3.
T4 ref.
FINAL
Page 33
Description
ACS8509 SETS
Default Value (Bin)
DATASHEET
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00000000
00000000
01110101
11111111
11111111
1XXXX000
XXX11111
XXXXXX00