Is high speed waveform display feature possible in TouchGFX?

[canbu22]

Is there a template or a sample application that one can use to develop fast running waveform display feature in TouchGFX? (such as that of a oscilloscope waveform display and not a static or slow speed 1-dim graph display)

if not any suggestions? ..thanks..

[Martin KJELDSEN · Accepted solution]

Hi canbu,

Could you define what you mean by fast-running? How large of a display and how large of a wave-form are we talking about? It's definitely possible, but depending on your needs, this may require a custom Widget that draws directly into the framebuffer; Something we've done for customers in the past to deliver specialized waveform/graph screens. We have examples of how to do standard graphs, but these are antialiased "Canvas" objects while drawing pixels straight into the framebuffer using interpolation could be faster.

Edit: Here's a simple application that shows how to use the Canvas Graph.

http://sw-center.st.com/touchgfx/TouchGFX/Community/GraphApplication.zip

Let me know!

Best regards,

Martin

[canbu22]

Hi Martin,

Thanks for the follow-up.

What I'm referring here is just a simple display of a waveform on a TFT or similar LCD display of size say 720x480 pixels that of any smart phone or even smaller sizes (similar to that you find STM32F746 Discovery Kit's LCD)

For example, we might want to display the live spectrum of an audio signal using an FFT and plot the Frequency Vs Magnitude using TouchGFX's canvas. This has to be live meaning continuously update the display waveform without any flickers or tearing, may be using double frame buffer scheme.

(see the attached snapshot of a similar live waveform display captured on a smartphone)

Since many STM32F4 & F7 devices have TFT LCD controllers as well as ChromeART 2D DMA capabilities, I'm sure it should be quite easy to implement these functionalities like how a Graphics Processor does.

I don't see any sample project implementing some thing like this using double frame buffering scheme in a STM32F4/F7 discovery kit (with reference to example projects by TouchGFX).

Would be great to have such a sample application using these schemes in TouchGFX say for a STM32F746 Discovery kit.

Regards

[Martin KJELDSEN]

Hi,

You probably won't see any sample projects like this, no. I have an example here on how to make a Graph using the Canvas widget. This would make the application a bit more memory intensive. i could share it with you if you're interested.

As far as DMA goes, using DMA for this kind of application would result in a lot of very small DMA operations and it might not be worth it - but i haven't done any measurements.

[canbu22]

Thanks for the update.

Appreciate if you could share your canvas example that you mentioned here..

(if you prefer to send privately, you may send to me at canbu22@yahoo.com)

[RCair]

Hi Martin,

Could you to send for me too?

cmelo.raul@gmail.com

[ASch]

Martin,

Could you to send for me too?

alessandrasch96@gmail.com

[canbu22]

FYI :

don't know reasons, but I have n't yet received any of these example codes or app notes as mentioned here.

[Martin KJELDSEN]

Hi @canbu22​,

Sorry for the wait. It slipped my mind. Here is a simple graph application.

http://sw-center.st.com/touchgfx/TouchGFX/Community/GraphApplication.zip

Best regards,

Martin

[canbu22]

Thanks Martin..very much appreciate it..