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SPI decode on multiple devices simultaneously

Question asked by transparenthack on Jul 30, 2020

Hi all,

 

I'm trying to debug a radio transaction between two devices by looking at the decoded data in/out from each of their transceivers.  I have an MSO-X 6004A oscilloscope and I was wondering if it would be possible to decode the SPI input/output from both transceivers simultaneously on the digital channels?  Both transceivers only have a single data line and a clock signal, as the data line is bi-directional.  I've taken a look through the user manual and it doesn't appear like there's a way to do this.  I thought about using the MISO/MOSI lines together to do this, however the clock lines wouldn't be synchronized properly, and I can't frame the different packets using the CS line for both.

 

This is important to me, as I really need to be able to see what the timing between each portion of the interaction looks like, and whether I'm sending/receiving the correct data on both ends of the transaction.  

 

So far, I've only attempted this on my older MSO6054A oscilloscope, which obviously can't do what I'm looking for.  I've attached a screen shot to the post of what the data looks like for both devices simultaneously taken from that scope so you have an idea of what I'm attempting to do.

 

As a side note, if this was a feature that currently exists, I would suggest also adding a feature that allows for multiple triggers...  That way, for longer transactions, I can trigger on both CS lines and not miss anything.  That is, if that feature doesn't already exist.  I don't know, I just received this scope last week and haven't had enough time to find all of the really cool new features that the MSO6054A (my next most advanced scope) just didn't have. 

 

Thanks in advance for your help!

 

-Chris

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