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Information processing
Information about state of the board is mainly processed by the DSP.
The main processes are:
•
Alarm detection.
Alarms related to optical signal or OFA module are detected and processed by DSP; a few
alarms related to HW in the board are detected by dedicated circuitry. All alarms are made
available to external interface block.
•
Measurement collection.
Measures of optical and electrical parameters are collected by DSP and made available to
external interface block.
•
Configuration and provisioning management.
Configuration and provisioning information from shelf controller via external interfaces are
managed mainly by DSP.
External interfaces
The following interfaces will be implemented:
•
Serial peripheral and Inventory Bus (SPI).
The SPI bus will be used by the main shelf controller to acquire remote inventory data; the same
bus is used by the main shelf controller to interface DSP processor. Data transfer over the SPI
bus is controlled by the main shelf controller; the other cards operate as slaves.
The SPI bus is duplicated on each shelf: each slave card is connected to both the main and the
spare SC processor through a dedicated bus.
•
Unit LED interface.
Two LEDs are on the front panel of the unit:
–
A bicolor red/green LED acting as:
•
Red: internal failure indication
•
Green: active unit indication
–
A yellow LED acting as shutdown indication (i.e. no amplification of optical signal).
Optical safety and shutdown handler block
Since optical power levels emitted by the preamplifier can damage the human eye, the unit will have to
be compatible with IEC standards, intended to protect users against optical radiation.
As protection mechanism, in the event of potential danger, an automatic shutdown will be supported.
Automatic shutdown will be implemented in the case of:
•
cover open (according enable from shelf controller)
•
loss of input signal
A single section automatic laser shutdown procedure will be implemented according G.664 Rec.
Restart pulses (time duration not higher than 300 ms) will be implemented.
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