If you still have a Philips PM3585 you can purchase  the PF8681/3x
pack which is a I2C signal disassembler.
Instead of the usual I2C logic signals you get an "english"
interpretation
of the bus activity, START, DATA WRITE AAH, STOP, etc.
As I know, Philips have already pull out of Test & Measurement
business, so don't know whether you can still get it.

I've seen some small handheld I2C bus analyzer in our Taipei
branch, if you need to know, I can find it out for you ?

Regards,

Peter Tiang
Design & Applications Lab
Hitachi Semiconductor(M) Sdn Bhd

=========================================================

>>> Engineering Department <imagelogic@IBM.NET> 27/August/1998 09:51pm
>>>
<Andy Kunz asked>
>>Does anybody have an I2C bus snooper?
<snip>

<Mike Harrison  responds>

> Philips do an I2C bus interface chip which can be used as a bus
> monitor. There is also a PC ISA card available using this chip,
which
> I think comes with monitor software, Let me know if you want details
&
> I'll dig it out.
> You could probably also do it using the I2C support in the larger
> PICs.


Are you thinking of the PCD8584?  I had a devil of a time interfacing
(logically) with that little bugger.  Works though, but I'm not sure
it
isn't simpler to bit bang a PIC.

There's an awful lot of bandwidth lost to the housekeeping on that
chip.
"Can I talk to you?" "Do you have data?" "Can I talk to you?" "Gimme
the data" and so forth.

Cheers,

Win Wiencke
Image Logic Corporation
ImageLogic@ibm.net