[AD2 - How does record work?]

@attila

Well that seem pretty useless, I thought the whole point of recording to disk was to save/stream unlimited lengths of data?

My screen looks as below and it indicates I could record 2hr.

[AD2 - How does record work?]

Hi @attila

I appreciate the tip about the pulse trigger. Stepping back for the big picture can you explain how the record data feature works and where the data is that I thought I captured? Why was there only a few seconds of data when I thought I captured for 40 minutes? My plan was to look at the recorded data and see what the state of the SCL line was. And is there a way to 'playback' recorded that say analysis can be done like the trigger you mention?

[AD2 - How does record work?]

Hi all, every time I use Waveforms, I seem to have trouble understanding some of the terminology or concepts.

I am trying to troubleshoot some I2C lines on a device that locks up after a 20-40 minutes. I thought the Record feature would stream and capture all the data, but I am not sure what to do with the data.

I let the record run for about 40 minutes, came back to the computer and saw the I2C lockup had occurred. I stopped the recording (default.bin). But what do I do with it? I tried File -> Import Binary and 'Show Entire capture'. It says the file has 42,329,550 bytes @ 7.692MHz. That is only  2.6seconds worth of data. Where is all the rest of the data that I thought I captured?

[USB1808X - Pattern match trigger]

55 minutes ago, JRys said:

For the digital pattern trigger to work, the program must be actively scanning the digital port. To read both analog and digital at the same time use the daq_in_scan function. When properly configured, it can simultaneously read analog + digital + counter. Take a look a the example daq_in_usb_1800.py.

To use pattern triggering add EXTTRIGGER to the daq_in_scan options (for example CONTINUOUS|BACKGROUND|EXTTRIGGER) and use set_trigger function to configure the pattern. The low threshold parameter is the digital pattern and the high threshold is the mask. For example set_trigger(board_num, TRIG_PATTERN_ABOVE, 3, 15)

 

 

Maybe I was not clear in my description. I am not trying to use daq_in_scan or to read analog and digital at the same time.

I am trying to use a_in_scan() with EXTTRIGGER. I wanted to trigger the ADC to start sampling based on me WRITING to the DIO OUTPUTS using d_out_scan(). I have a feeling this is a limitation or bug in the firmware. The documentation states that EXTTRIGGER digital pattern matching should work when a specific pattern is present on the DIO port. It does not state that pattern needs to be as result of input. I am creating that required pattern on the port as an OUTPUT.

I did work around this issue by adding an additional loopback wire from a DIO output to the ITRIG since pattern matching is not working. I tried to go the pattern matching route since the datasheet claims lower latency for that.

[USB1808X - Pattern match trigger]

I am unsure if what I am trying to do will work, though I feel that it should...

- I setup digital port to OUT direction and set value 0 - I am going to use use both DIO0 and DIO1

- I use set_trigger() with a pattern match of ABOVE 0 and MASK 3 so that the AIN is triggered when digital output DIO0 or DIO1 is HIGH. NOTE: I am using the DIO0 as an output.

- I setup background a_in_scan with EXTRIGGER option to capture 20000 data points.

- At this point I am ASSUMING a_in_scan() is waiting in the background for the pattern match on DIO0 / DIO1 values. I ASSUME the pulse I generate writes a high value to the port which triggers AIN.

- I perform d_out_scan() to generate a pulse waveform on DIO0 (verified on a scope as 50ms)

It seems the a_in_scan never triggers because when I call get_status(), its status is stuck as RUNNING.