Invalidated widgets flickering

[MVils.1]

We use TouchGfx with a STM32f769 on a custom board. There are many ui widgets like textarea, boxes and buttons. At first the display had a flicker problem. That was solved with just invalidating widgets that should update.

Now the problem is that if a single widget updated with .invaldate(), an other widget - which was previously invalidated - is suddenly flickering.

I found that this occurs with double buffering activated.

Any ideas that could help?

Thanks in advance.

[franck23]

Hi,

Maybe you are reaching the maximum bandwidth of your SDRAM.

What is your screen size, bit per pixel, and SDRAM width (8, 16 or 32bits)?

[MM..1]

How version TouchGFX you use, and generated code is from CubeMX?

[Romain DIELEMAN]

The fact that this happens only with double buffering makes your statement my first guess as well. @MVils.1​ Have a look at your mapfile (.map) and check your memory usage.

/Romain

[MVils.1]

@Community member

800 x 480 x 16 bpp and SDRAM width is 32bits. LTDC clock 27.375 MHz.

@Romain DIELEMAN​ 

Memory usage looks good. I don't know how to check sdram memory usage, but it's a 128 M and this should be enough ..

[MVils.1]

I tought that TouchGfx is always at latest version in cubemx because i check updates often. Just now i saw that you have to migrate the TouchGfx version for your project too. Thanks for the hint.

[franck23]

With your config, you shouldn't hit the SDRAM max bandwidth.

Maybe check that your FMC is set to run at 100MHz.

[MM..1]

You dont reply numbers , but you can check my example BUGREPORT TouchGFX 4.16 strange display

[MVils.1]

Old version was 4.15. Now i migrated to 4.16. I had a strange memory access problem after the update. Could only solve it with a complete regeneration of the cube ide project. But sadly the trouble with flickering widgehts still persists.

[MVils.1]

FMC is set to 108 MHz. I read that max is 100 MHz but lowering that didn't help.