ACS8525T Semtech, ACS8525T Datasheet - Page 58

• Manufacturer Part Number: ACS8525T
• Description: Line Card Protection Switch for SONET/SDH Systems
• Manufacturer: Semtech

Address (hex):
Revision 3.01/August 2005 © Semtech Corp.
ADVANCED COMMUNICATIONS
Register Name
auto_extsync_
en
Bit No.
Bit 7
7
6
5
4
3
2
1
0
34
cnfg_input_mode
phalarm_time-
out
Description
auto_extsync_en
Bit to automatically disable the external Frame Sync
input following a source switch.
phalarm_timeout
Bit to enable the automatic timeout facility on phase
alarms. When enabled, any source with a phase
alarm set will have its phase alarm cancelled after
128 seconds.
XO_edge
If the 12.800 MHz oscillator module connected to
REFCLK has one edge faster than the other, then for
jitter performance reasons, the faster edge should
be selected. This bit allows either the rising edge or
the falling edge to be selected.
Not used.
extsync_en
Bit to select whether or not DPLL1 will look for a
reference Sync pulse on the SYNC1/2/3 input pins.
Even though this bit may enable the external Sync
reference, it may be disabled according to
auto_extsync_en.
ip_sonsdhb
Bit to configure input frequencies to be either
SONET or SDH derived. This applies only to
selections of 0001 (bin) in the
cnfg_ref_source_frequency registers when the
input frequency is either 1544 kHz or 2048 kHz.
*The default value of this bit is taken from the value
of the SONSDHB pin at power-up.
Not used.
reversion_mode
Bit to select Revertive/Non-revertive mode. When in
Non-revertive mode, the device will not
automatically switch to a higher priority source,
unless the current source fails. When in Revertive
mode the device will always select the highest
priority source.
Bit 6
XO_edge
Bit 5
Description
Bit 4
FINAL
Page 58
(R/W) Register controlling various
input modes of the device.
extsync_en
Bit Value
Bit 3
0
1
0
1
0
1
0
1
0
1
0
1
-
-
ip_sonsdhb
Value Description
External Frame Sync enabled/disabled according to
extsync_en.
External Frame Sync enabled if extsync_en = 1 until
a source switch. After this it is only re-enabled by
writing “1” to extsync_en again.
Phase alarms on sources only cancelled by
software.
Phase alarms on sources automatically time out.
Device uses the rising edge of the external
oscillator.
Device uses the falling edge of the external
oscillator.
-
No External Frame Sync signal on selected Sync
input- SYNC1/2/3 pins ignored.
External Sync derived from selected Sync input-
SYNC1/2/3 pin- according to auto_extsync_en.
SDH- inputs set to 0001 expected to be 2048 kHz.
SONET- inputs set to 0001 expected to be
1544 kHz.
-
Non-revertive mode.
Revertive mode.
Bit 2
Default Value
ACS8525 LC/P
Bit 1
DATASHEET
www.semtech.com
1100 1010*
reversion_mode
Bit 0