Start a new topic
Not Taken

Scroll / tab /swipe

Hi is it possible to have scroll or tab function , just wondering if is possible that if the data on screen gets filled up it automatically starts to scroll , 


1 person likes this idea

if you are using "scroll" like what happens in a long webpage, then no.

if you are taking about the scrolling text component - it is already in there.

if you are referring the programming technique of "scrolling"

  • loosing the top line of text,
  • moving each remaining line up one slot
  • erasing bottom line
  • adding new text into new line
and you are referring to non graphical content - it can be coded via your mcu.

There isn't an "automatic" scrolling.  This is an illusion created by good programming.
If you code your MCU to be aware of what space remains, then you are able to trigger "the scroll" at the appropriate time ... it looks mostly automatic - but it really was your detailed code.

Thanks , You answered me I was wondering to if possible to design or program a scroll like a web page  / like in mobile here you can change pages via swipe ( tab function ) 

On completely unrelated to above topic , is there way where higher memory can be used to upload the HMI , I am using 2.8 " 320X240  basic model , I am wondering if project of higher size can be installed in the sd card and if it can be run .

Thank YOU 

To work with the why a webpage scrolling could not work, you have to look at the specs for the MCU chip on the back of the Nextion.  As the basic model has 8K of RAM  and 64K of flash which is shared between the firmware and the active portion of your the HMI design.  For storage you have 4M or 16M of flash on the basic models, 16M or 32M of flash on the Enhanced Models.  The screen itself has a limited amount of SGRAM, on the smaller screens where the SGRAM is internal and there is no external chip - to scroll you will probably need space to store "your other pixels" that have scrolled off the screen to swap them out. Remembering that each pixel needs 2 bytes of space on the display - you simply don't have the memory to do so.

At the moment there is no means to store on the SD card on the nextion short of putting the single TFT file on for uploading.  Now you could put multiple TFT files on an SD card that attaches to your connecting MCU and "swap programs" on the Nextion.  This would need to be done from your MCU over serial to the Nextion.  What you are going to find is if you are looking for larger size than the 4M of Flash, is that you have to consider is when the "transfer" to swap programs out occurs.  4M transfer takes around 6:40m at top speed of 115200 baud.  This certainly could be done daily in the middle of the night when you expect  no one would be watching - but it certainly couldn't be done without someone not noticing that everything has stopped and your nextion is displaying "37%" a it is updating for ~ 7 minutes.

The total transfer time of 1GB SD card would be ~28.4 DAYS over serial at top speed.

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

- request not realizable.

Login or Signup to post a comment