FTGN2117P2xxN Product Specification
Finisar Corporation – October 2015 Rev C1 Page 4
VI. Digital Diagnostic Functions
Finisar GPON Stick support the 2-wire serial communication protocol as defined in the SFP
MSA
3
.
Additionally, Finisar GPON Stick (SFP-ONU) provide a unique enhanced digital diagnostic
monitoring interface, which allows real-time access to device operating parameters such as
transceiver temperature, laser bias current, transmitted optical power, received optical power
and transceiver supply voltage. It also defines a sophisticated system of alarm and warning
flags, which alerts end-users when particular operating parameters are outside of a factory-
set normal range.
The SFP MSA defines a 256-byte memory map in EEPROM that is accessible over a
2-wire serial interface at the 8 bit address 1010000X (A0h). The digital diagnostic
monitoring interface makes use of the 8 bit address 1010001X (A2h), A0h stores static
information including product and vendor IDs while A2h contains real-time diagnostic data.
The operating and diagnostics information is monitored and reported by a Digital
Diagnostics Transceiver Controller (DDTC) inside the transceiver, which is accessed
through a 2-wire serial interface. When the serial protocol is activated, the serial clock
signal (SCL) is generated by the host. The positive edge clocks data into the SFP
transceiver into those segments of the EEPROM that are not write-protected. The negative
edge clocks data from the SFP transceiver. The serial data signal (SDA) is bi-directional for
serial data transfer. The host uses SDA in conjunction with SCL to mark the start and end of
serial protocol activation. The memories are organized as a series of 8-bit data words that
can be addressed individually or sequentially.
For more information, please contact Finisar.
Digital diagnostics for the GPON Stick (SFP-ONU) are internally calibrated by default.
