FTLF1721P1xCL Pluggable SFP Product Specification – September 2008

F i n i s a r

© Finisar Corporation September 3, 2008 RevA.1

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Additionally, Finisar SFP transceivers 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 E

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), so the originally

defined serial ID memory map remains unchanged. The interface is identical to, and is

thus fully backward compatible with both the GBIC Specification and the SFP Multi

Source Agreement. The complete interface is described in Finisar Application Note AN-

2030: “Digital Diagnostics Monitoring Interface for SFP Optical Transceivers”.

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, Mod Def 1) is generated by the host. The positive edge clocks data into the

SFP transceiver into those segments of the E

negative edge clocks data from the SFP transceiver. The serial data signal (SDA, Mod

Def 2) 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 see the SFP MSA documentation

Note AN-2030.