FTRX-3811-3xx DWDM XFP Product Specification – September 2007

F i n i s a r

© Finisar Corporation 28-September-2007

Rev C1

Page 8

VIII. Digital Diagnostics Functions

As defined by the XFP MSA

functions via a 2-wire serial interface, which allows real-time access to the following

operating parameters:

• Transceiver temperature

• Laser bias current

• Transmitted optical power

• Received optical power

• Transceiver supply voltage

It also provides a sophisticated system of alarm and warning flags, which may be used to

alert end-users when particular operating parameters are outside of a factory-set normal

range.

The operating and diagnostics information is monitored and reported by a Digital

Diagnostics Transceiver Controller (DDTC) inside the transceiver, which is accessed

through the 2-wire serial interface. When the serial protocol is activated, the serial clock

signal (SCL pin) is generated by the host. The positive edge clocks data into the XFP

transceiver into those segments of its memory map that are not write-protected. The

negative edge clocks data from the XFP transceiver. The serial data signal (SDA pin) 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. The 2-wire

serial interface provides sequential or random access to the 8 bit parameters, addressed

from 000h to the maximum address of the memory.

For more detailed information, including memory map definitions, please see the XFP

MSA documentation