Add a Rolling Capture mode


Add a capture mode that keeps the last "X" samples or "X" seconds worth of data, and discards any data before this period.

I am watching an I2C line, and if everything goes well, there will be traffic every 1 second. I am interested in this traffic immediately before and after my device crashes, at which point no more data is communicated on the I2C lines. In order to catch this, I need to constantly be capturing, until I run out of memory, and restart the capture. There is no good way to trigger or script this using the socket API, but I'm open to suggestions...


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photomankc Jul 11, 2018
All I can say is yes, please! I'm currently trying to debug a very intermittent problem possibly with I2C. Without this feature I can't really track it down as it takes multiple hours to happen. Something along the lines of trigger after X.XXX secs of no-start or no-data condition would be a huge help!

GammaJet Jul 11, 2018
I agree fully with robgee1964. I need to run a test over several days to catch a sporadic error, and this would work only with a circular buffer...

robgee1964 Jul 11, 2018
Totally agree with this, what's needed is a circular buffer that stores whatever pre or post trigger samples have been specified, this is how oscilloscopes and many other logic analysers work. Currently, if you are capturing whilst waiting for an infrequent error trigger, it *looks* as though it just gathers all samples, albeit to some temporary buffer.
To be honest I see the lack of this feature as a significant limitation in otherwise very decent product.

YBt Jul 11, 2018
This would be very useful for overnight tests. Let the system run and acquire as many triggered events as there are instead of only one. The triggered event could be saved into a tab and/or to the disk before restarting the trigger.

Mark Garrison Jul 11, 2018
You might be able to do that right now with the socket API: github.com/saleae/SaleaeSocketApi
You can automate the start -> save to disk -> restart operation. If you have more questions about it, please contact support.

Gunther Jul 11, 2018
Sounds similar to what I could use right now. Additionally I would like the option to save each capture to file with a simple index number appended to the filename. Wait trigger->triggered->capture data->save to disk-> rearm trigger.

Randy Jul 11, 2018
Got a really tough problem to track here that requires this particular function. It's the only way to find problems that happen once in awhile...

FST Jul 11, 2018
For me it would be useful to have all the communication on I2C or SPI up to the Crash. With the oscilloscope, to measure that, I use the normal Trigger mode. Same time I sniff the Serial bus (only the transferred data are saved). With this two tools I'm sure to have the capture on the last sequence and to memories the flow up to the Crash. It would be fine to have both on the Saleae tool.

DeanAtPCS Jul 11, 2018
This would be very useful for me too. Being able to trigger multiple captures and only record X amount of information before and Y amount of information after would make my testing easy.

Adrian-Autoliv Jul 11, 2018
I would like the "max amount of memory" idea.

rkeebo Jul 11, 2018
Or set a maximum amount of memory to use and handle it as a circular buffer. I would use this 'mode' more than any other.

nweltd Jul 11, 2018
I'd like to see this feature, where x amount of data is captured and capturing stops on a trigger event

Guest Jan 11, 2019
Seems to be duplicated by ideas.saleae.com/ideas/SALEAE-I-17

There's also a suggestion how that's already possible with a beta release.

Still I really need that feature as well and would like to see it come live soon!

Guest Jan 28, 2019
Please, please, please implement this feature!!!! All traditional logic analyzers have this capability. Having triggers that can only start a capture is kind of brain damaged. You should be able to define a capture period and place the trigger anywhere in that range.