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Updating waveform from any page and not loosing data when going to waveform page.


I was wondering if anyone have found a way to solve the below problem without using (scares) memory on the MCU.

I use a Mega 2560 as MCU and uses a Nextion enhanced 5” screen. I have very little if any logic (programming) on the Nextion. I use components as forms on different pages and then send data from the Mega to the screen to display.

My project has 9 different page of which one of them, page 5, is displaying a waveform that I update every 10 seconds. As I want to display data over a long period of time, a few hours at least, I would like to be able to send data to the waveform using the “add” command from my program on the Mega.

Now all of this is working 100% fine and looks very impressive, whilst I am on page 5. This is where I have a two request.

1. If I move to another page then I cannot any longer send data to the waveform to keep updating it. My request is that we can send data to “page id”+”waveform channel”, or something like this, to keep the updating of the waveform up to date, even from different pages.

2. Secondly when I go to another page using the page id command, and then return to page 5, all the previous data is lost as the page refreshes. My request – is there any way that we can change pages and return the a waveform page without losing the previous captured data in the waveform?

I am now reviewing all of the Feature Requests, this will take some time, patience please.

Hey Jan,

I am not sure that the viability is as there could 4 channels x up to 800 data points to retain. 6400 Bytes

Trying to retain these values in SRAM doesn't provide enough room to execute newly loaded page.

However, I have put these two requests to carry forward to be investigated further.

Regarding this from your Mega side, Perhaps it is possible to keep these values local on the Mega in a cyclic buffer that when you are not on the waveform page, it is still added to the Mega buffer, and on returning bring the waveform uptodate with the addt command.

Hi Patric

Perhaps it might help push them for the next hardware version to go for a more memory rich platform.

For now I use a SD-Card on the Mega to log data to and then replay it from there.

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