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Complex Triggering -- Thoughts?

A project log for sdramThingZero - 133MS/s 32-bit Logic Analyzer

Add an old SDRAM DIMM to your SBC for a 133MS/s 32-bit Logic Analyzer, add ADCs for a Scope...

eric-hertzEric Hertz 04/14/2016 at 12:270 Comments

Complex-triggering is another feature that would make this system a bit more useful...

There was discussion about it in the HaD Blog article, but I haven't really thought too much about what *types* of triggering would be useful... so I'm reaching out to my readers!

I can only think of a couple, off-hand...

The first is, obviously, looking for a specific bit-pattern on certain bits *in parallel*/simultaneous. I think this should be pretty simple with maybe a few XOR gates and some fancy "code" in the "Free-Runner."

The second is looking for a specific bit-pattern in serial form on a single data-bit. I think this, too, can be handled with Free-Running "code" by implementing a state-machine, and *maybe* a bit of that same XOR logic from before.

It gets a bit more complicated, though, when thinking about whether we're looking for a serial pattern or whether we actually need to consider the bit-rate, etc. (is there a clock source? Are we doing SPI or UART or I2C?)

And then... I'm not really certain what other types of complex-triggering exist/might be handy in order to even start thinking about whether they could be implemented in the "Free-Runner Code", so if you've some ideas regarding various sorts of commonly-useful complex-triggers, please share!

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