STM32F429 Disco LCD flickering with STemwin Hello World example in TrueStudio

[MRyan.7]

Using CubeMX 5.3.0 to autogenerate a sample STemwin example set of code for TrueStudio seemed to work well. It was created choosing the STM32F429 Disco board and adding the STemwin graphics options...no customization of any settings was done. The project compiled and ran no issues...except....

When running under the debugger (or after code has been loaded and the system has been reset separate from debugger), the screen is flickering as if some other set of data is being interlaced. You can see the "hello world" and some other minor text/graphics that were added to it when it is doing this. It looks like this:

However, if I run under the debugger and then halt the debugger, the flickering stops and we have the expected image:

Since these are default settings and STM hardware, we expected there to be no tailoring of SDRAM settings, LTDC, etc.

Loading stock demo code (binary) into the board resulted in normal LCD operation also, so there are no hardware issues.

Has anyone else seen this? If so/not, do you have any suggestions on how to debug or try to determine the root cause? We are just getting our feet wet on this platform before moving to a custom platform, and want to understand as much as we can about the use of the STM32F429 and STemwin capabilities.

Thank you!

[MRyan.7]

Using the same setup but generating for Keil MD V5 produced the same results (except that stopping debugging did not stop the flicker in this case).

[MRyan.7 · Accepted solution]

This person also had the same problem. Fix is to reduce the LCD clock frequency (reduced mine by a factor of 4 (/2 to /8 on last divisor). Works now.

https://community.st.com/s/question/0D50X00009yGS3SSAW/cannot-run-a-simple-hello-world-application-on-stm32f429idisc1-board-with-stm32cubemx-and-stemwin