ACS8515Rev2.1LC/P Semtech Corporation, ACS8515Rev2.1LC/P Datasheet - Page 30

• Manufacturer Part Number: ACS8515Rev2.1LC/P
• Description: Line Card Protection Switch For Sonet or SDH Network Elements
• Manufacturer: Semtech Corporation

Ultra Fast Switching
Ultra Fast Switching
External Protection Switching
External Protection Switching
Ultra Fast Switching
Ultra Fast Switching
Ultra Fast Switching
A reference source is normally disqualified after
the leaky bucket monitor thresholds have been
crossed. An option for a faster disqualification
has been implemented, whereby if register 48H,
bit 5 (Ultra Fast Switching), is set then a loss of
activity of just a few reference clock cycles will
set the ‘no activity alarm’ and cause a
reference switch. This can be chosen to cause
an interrupt to occur instead of, or as well as,
causing the reference switch.
External Protection Switching
External Protection Switching
External Protection Switching
Fast external switching between inputs SEC1
and SEC2 can also be triggered directly from a
dedicated pin (SRCSW).
activated either by holding this pin high during
reset, or by writing to bit 4 of register address
48Hex.
Once external protection switching is enabled,
then the value of this pin directly selects either
SEC1 (SRCSW high) or SEC2 (SRCSW low). If
this mode is activated at reset by pulling the
SRCSW pin high, then it configures the default
frequency tolerance of SEC1 and SEC2 to +/-
80 ppm (register address 41Hex and 42Hex).
Revision 2.00/September 2003
Figure 9. Inactivity and Irregularity Monitoring
Figure 9. Inactivity and Irregularity Monitoring
Figure 9. Inactivity and Irregularity Monitoring
Figure 9. Inactivity and Irregularity Monitoring
Figure 9. Inactivity and Irregularity Monitoring
ADVANCED COMMUNICATIONS
leaky bucket
response
reference
source
alarm
Semtech Corp.
This mode can be
inactivities/irregularities
30
Any of these registers can be subsequently set
by external s/w if required.
When external protection switching is enabled,
the device will operate as a simple switch. All
clock monitoring is disabled and the DPLL will
simply be forced to try to lock on to the
indicated reference source. The operating state
(sts_operating_mode register) will always
indicate ‘locked’ in the mode.
Activity Monitoring
Activity Monitoring
Activity Monitoring
Activity Monitoring
Activity Monitoring
The ACS8515 has a combined inactivity and
irregularity monitor. The ACS8515 uses a ‘leaky
bucket’ accumulator, which is a digital circuit
which mimics the operation of an analog
integrator, in which input pulses increase the
output amplitude but die away over time. Such
integrators are used when alarms have to be
triggered either by fairly regular defect events,
which occur sufficiently close together, or by
defect events which occur in bursts. Events
which are sufficiently spread out should not
trigger the alarm.
setting threshold, the point at which the alarm
is triggered can be controlled. The point at which
programmable fall slopes
ACS8515 Rev2.1 LC/P
By controlling the alarm-
(all programmable)
upper_threshold
lower_threshold
bucket_size
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FINAL