Waveforms not showing any "waveforms"

[PhilipJ]

So yesterday I received my new Digital Discovery and got started capturing some waveforms and even decoding them with the UART protocol analyser. I managed to trigger on specific protocol bytes, all going well.

This morning I've started by loading the same Workspace and nothing is displayed all inputs are shown as logic high levels (even though I have enabled the pull-downs in the Power Supplies TAB).

So I've reverted to simple waveforms, no protocol involved. I've set a negative edge trigger on "DIN 0" (I assume this is the input labelled HIGH SPEED INPUTS on the unit?) and connected it to my logic board (with a GND as well). I am set to 100MHz clock and 4M samples.

My problem is, when I click on "Single" I see config'ed trig'ed done but there is just a high logic level displayed with no sign of the waveform!!

I know there is signal on the input because I have an oscilloscope connected to the same pin and that shows me a clear 0 to 3.3v UART logic waveform repeating.

Can you suggest what is going wrong?

PhilipJ

 

[PhilipJ]

OK, don't worry too much about this, after several times shutting down Waveforms and starting it again without loading the old Workspace it is drawing the waveforms ok again.

PhilipJ

 

[attila]

Hi @PhilipJ

Wasn't the horizontal trigger position out of the screen ?

[PhilipJ]

On 8/16/2022 at 9:48 AM, attila said:

Hi @PhilipJ

Wasn't the horizontal trigger position out of the screen ?

Hi, that is possible, I'm still getting used to the interface. At first I thought the trigger position was always in the centre of the screen with 1/2 the captured samples to the left and 1/2 to the right but I have now caught onto the zooming and scrolling stuff. It would be nice to have a button that brings the trigger point back to centre for those times when we're zoomed in quite a lot.

thanks for replying

Regards

PhilipJ

[attila]

Hi @PhilipJ

Double click on the bottom axis.

[PhilipJ]

Hi Attila,

thanks for the info, I am getting a bit more used to the user interface now.

Your highlighted bit above; does this actually change where the trigger point is in the capture buffer? or jusr where stuff is displayed on the screen? What I mean is, can I set the DDiscovery to record a buffer full of data up to (and including) a trigger event or alternatively a buffer full of data starting at the trigger event and showing what happened afterwards? Ideally anything in between (probably in % as down to the individual sample level would be crazy if I had set it to 64M samples).

I am making a lot of use of the protocol analysers in my Logic Workspace to capture UART comms in a multiprocessor system, I like the way it displays the serial bytes/characters but I am capturing a lot of data (~100mS at 230400 baud)  so it would be nice to be able to search within the protocol waveform for a particular character or hex byte. Is this possible?

Finally (for now :-)) - I like the opportunity to trigger on a UART character but it would be REALLY amazing if it were possible to trigger on a 2 character pattern - a lot of my protocol is based on a command header of 2 ASCII characters such as "LC" and commands terminated with "\r\n"

I know there is a lot in the UI and I have a lot to learn, but so far I am really glad that I bought this product.

regards

PhilipJ

 

 

[attila]

Hi @PhilipJ

In Repeated and Scan capture modes the trigger position and time base adjustment will affect the next capture.
In Record mode these can be configured with the Config button before Record.

For search use Filter option in the View/ Event and you may can configure Hexadecimal, HexASCII, ASCII format under the UART channel properties.

The next version will support triggering on up to 3 consecutive chars.

[PhilipJ]

Thanks for the info, I will try the Filter stuff.

Looking forward to the next version, triggering on 3 consecutive characters sound perfect :-)

regards

PhilipJ

 

[attila]

Hi @PhilipJ

It is already available: