Digilent AD3 and Righol DHO804 reading I2C easy on AD3 challenging on DHO804

[glenmann]

Dave J. did a great job convincing me to invest in Digilent's AD3 and Rigol's DHO804 for my son's new EE lab at home.  Both are outstanding value IMHO. 

To guide my "EE in training", I decided I2C would be a fun way to introduce him to board level communications.

The issue I am having is the AD3 does an excellent job of generating/decoding I2C right off the start.  The Rigol, is a head scratcher.  I know it can be done because this post shows me what I am trying to arrive at. 

https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/450/


Can someone direct me to an article/video on how to setup the Rigol DHO804 to decode the I2C?  I know I have good I2C signals, because the AD3 shows me the self generated signals and I can connect it to an Arduino we set up to populate a 4x20 LCD with I2C.  I even put 4.7K pull up resistors on the Arduino I2C to ensure I have sufficient signal, but the Rigol refuses to reveal the I2C decoded signal from the AD3 generated I2C or the Arduino.

Thanks in advance.

Cheers, Glen

[rstofer]

I2C is a tough protocol mainly because of the Start condition and this is what you need to trigger on.  The scope will do the work if you get all the parameters correct and the manual gives a step-by-step example.  Try their approach first...

https://www.batronix.com/files/Rigol/Oszilloskope/DHO800/Manual/DHO800_UserGuide_EN.pdf

Document page 177, pdf page 191 and onward...

[RogerG]

@glenmann:

Please be aware that there's a bug at serial decoding at DHO800/900. You always have to set a 1x probe multiplier for both used I2C channels, even when your probes are at 10x (what they normally should be). Maybe this helps to solve your problem.

We all hope that Rigol is coming soon with a big FW update to solve (most of) the pending problems.