How to save a bit sequence from oscilloscope?

Question

I'm using two wires to communicate between devices. First wire is a clock, second is a data bit. Logic is simple: master device (AVR ATMega in my case) sets a value on the data pin, then raise "1" on the clock pin. After that, slave device (ATtiny) reads that bit and waits for the next rising edge.

To be sure that I'm sending the correct bits from the master to the slave, I've connected an oscilloscope to the clock and data lines. Please see a snapshot (yellow is a clock, red is a data):

As you can see, there are eight raising edges of the clock. Also pulse width is different, it can't be less than 1ms, but there is no max limit: clock may keep "0" or "1" for seconds, minutes or even hours.

This sequence send "1, 1, 0, 1, 0, 0, 1, 0" or 0xD2. So my question is: How can I configure my oscilloscope to get this bits/byte?

I'm aware that I can capture RAW voltage information, but in my case there only two voltage levels: 0V and +5V. It would be awesome to capture only edge changes info.

P.S. My oscilloscope is Instrustar ISDS205A

You need to use the logic analyzer capability of your scope instead of the scope itself. — vini_i
– vini_i, Commented Feb 3, 2019 at 14:13
@vini_i thaks for the tip, but I can't find this option in menu (I see only Spectrum Analyzer and Lissajous). Does it mean that this feture is not avaliable for my oscilloscope model? Or I'm just blind and can't see it? — Aleks Andreev
– Aleks Andreev, Commented Feb 3, 2019 at 14:22
You may want to look up the term setup time. It would be wise to update the dataline on the falling edge and let the slave clock in on the rising edge. — sstobbe
– sstobbe, Commented Feb 3, 2019 at 14:58

SamGibson · Accepted Answer · 2019-02-03 15:16:05Z

As stated on page 4 of the user manual for your ISDS205A scope, that model does not include the optional logic analyser functionality, which would be the usual way of capturing the digital representation of the waveform.

The manufacturer claims that it does include a "Data Recorder", which is described in the "Data Recorder.pdf" manual. That document is currently available within this 21MB zip file (although the link might change with later software versions) on the "Software and Driver Download" page.

However, from their description, this "Data Recorder" seems to be the streaming ADC output (i.e. capturing the digitised analog voltage). This is probably what you described as the "RAW voltage" capture and seems to be the best you can do with that scope.

Alternatively, buy a cheap USB logic analyser (many of those sold are similar to the Cypress FX2-based option fitted to other models of that scope) and use the Sigrok open-source software to control it.

Sad to hear this :( Anyway thank you for your time. Also thanks for fixing errors in my question (still have a problems with English) — Aleks Andreev
– Aleks Andreev, Commented Feb 3, 2019 at 14:55
@Aleks - You're welcome, sorry that scope doesn't include what you wanted. I've found the document"Data Recorder.pdf" and updated that in my answer. (Your English is very good! I was just tidying-up the slightly rough edges of spelling/grammar :-) ). I recommend you look at the available USB logic analysers. Again, the basic ones stream data to your PC (like that scope), and don't just record the edges. But once you have the data file on the PC, then you can view the edges in the PC software. There are more-expensive logic analysers which can send just state change data across USB to the PC. — SamGibson
– SamGibson ♦, Commented Feb 3, 2019 at 15:14

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