Forum: µC & Digital Electronics every sfp with a twi?

von thresholder (Guest)

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do all SFPs have a Two wire interface?
Also DACs?
I saw some with i2c in some shops...

In SFF 8431 is a description of twi:


But it doesn't describe the information which can be read right?
It referres to:

"SFP+ management memory map is specified by SFF-8472."

And it sais:

"this document defines an enhanced memory map with a digital diagnostic 
monitoring interface for optical
transceivers that allows pseudo real time access to device operating 

* So is it only a must-have for optical SFPs?

* Or a must-have for all SFPs?

* Do I need to configure it always first? (with my NIC it works fine I 
guess. but another devices doesnt connect..)

Thank you :D

von thresholder (Guest)

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On the Pinout it says
MOD-DEF2  and 1 is there for 2 wire serial..


It looks like it is not really optional..

von thresholder (Guest)

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ah I just did ethtool -m with my 10G card and it found my DAC EEPROM via 
i2c xD

I think with this I can find it out for each device^^


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