Framebuffer shifts across the screen in runtime

[JSime.1]

I am using similar hardware to the stm32f469i-disco however the screen is a st7701 and is ran in video mode (burst mode) with double buffer.

I have added a video below showing the issue, for context the framebuffer doesn't shift with quick interactions however it will shift with longer interactions such as in the video, what is shown is a colour picker map, when moving across the map to choose the colour sometimes the screen will shift horizontally in portrait mode to the right of the screen, sometimes it can be slight shifts and sometimes it can be extreme shifts. The shift of framebuffer that is shown on screen will stay like that however the touch zones for the touch panel have not shifted.

Has this happened to anyone or would you have any insight as to what could be the cause of the issue?

[achille]

I also have similar hardware to stm32f469i-disc. I am looking to replace the lcd with a new condriver st7701s. The gui are written with touchgfx. I am having some problems getting this driver to work. Could you please share your firmware?

[reoxthen]

That almost feels like your frambuffer starts from the middle of the top hline of the screen which causes a cascade effect shifting everything in your framebuffer consistently. It may be a synchronization issue. Maybe the transfer from your framebuffer to the display can't keep up with your pclk frequency (remember ST7701S doesn't have a gram, so you have to constantly refresh). How about slowing down your pixel clock and giving it another try? 

 

you could also try to make sure your pulse width, front and back porch are correct.