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Trigger on UART pattern?

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Trigger on UART pattern?

Postby wxbeaz » Fri Mar 25, 2016 12:59 pm

Since I haven't had any luck in the windows sub-forum I thought I would try here.

Is there any way to setup a 2204 or 2208 to trigger solely on a UART hex data series string? i.e. look for 55 0D 08 then start capture.

If not the 2000 series, are any of the other picoscope series' capable of triggering on a data series?

This really sounds more like a software feature to me, or is it already capable and I can't figure it out?

Thanks
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Re: Trigger on UART pattern?

Postby bennog » Mon Mar 28, 2016 7:50 am

You have to write your own software to do this.

The serial decoding (any decoding) is done after the data is captured.
So it is impossible to trigger on a decoded pattern.

However it is possible to do int with the SDK and a lot of effort :)
I have done it before with CAN decoding in real-time (this was a 500kbps CAN data stream)
So a 9600 bps or 115.2 kbps can be done in software with the SDK in real time.

The main problem is the SDK wont support save the data in .psdata files so it is impossible to see the data in picoscope.

You can also use a audrino or a raspberry pi to listen to the serial data and toggle a GPIO pin when the data is seen on the serial port, you have a trigger signal to trigger the scope (the trigger will always be after the data is occurred).

Regards,
Benno
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Re: Trigger on UART pattern?

Postby wxbeaz » Mon Mar 28, 2016 1:19 pm

Thanks for the response bennog!

I think I already knew the answer, thanks for the confirmation.

Your idea of an arduino to listen then trigger is a great idea!
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Re: Trigger on UART pattern?

Postby alan » Mon Mar 28, 2016 6:19 pm

If you use one of the deep memory oscilloscope then you can collect / decode huge amounts of serial data. The filter command can then be used to search / find any specific data string you are after.

For the 2000 series with smaller internal memories this is still possible for slower serial protocols - they can capture 100,000,000 samples of data in USB streaming mode. Max sampling rate in PicoScope for this mode is 1MS/s.
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