Easiest/Cheapest way to snoop I2C traffic?

[Nigel Goodwin]

Thankes Mike. Unless I'm missing something, I don't think it would work though. For 2 or more channels, the sample time listed is 2us. At 400KHz, or 2.5us per bit, wouldnt that make the reading unusable? You wouldn't be able to see the quick transition points like START, ACK, and STOP.

You can't really do I2C slave in software, you need a little hardware as well, a couple of gates can be wired to give an indication of a START pulse, and the PC I2C devices I mentioned earlier generally did that.

 

[Fred.Amoson]

I don't know what your budget is, but this looks like it would do the job easily:

https://www.pctestinstruments.com/

 

[Nigel Goodwin]

I don't know what your budget is, but this looks like it would do the job easily:

Well he did say 'cheapest', but it looks a pretty impressive tool - well worth posting!.