Basic TouchGFX application don't work

[Luca1]

Hi to all!

I'm not able to run a very basic (a black screen) TouchGFX application on my hardware. I have follow the TouchGFX documentation and the STM32L496G-DISCO application example, but i wasn't lucky..

In particular I never reach the breakpoint that i put in the TouchGFXHAL::flushFrameBuffer(const touchgfx::Rect& rect) method. Also, if I suspend the debug, i see that the application stack arrive at the method touchgfx::HAL::lockFrameBuffer().

I have modified only the TouchGFXHAL class, in attatched there are this class files, following the documentation and the example metioned above, but maybe i miss something.

Please someone can give me some help?

[Martin KJELDSEN]

Are you hitting breakpoints in setupScreen() of your views? Are you hitting breakpoints in your LTDC/DSI interrupt handlers (If not, then the application won't get ticked, and flushFB will never get called) ?

[Luca1]

Hi Martin thank you so much for the reply!

Yes i hit the breakpoint in my setupScreen of my view (../TouchGFX/gui/src/screen1_screen/Screen1View.cpp), but this method don't contains nothing, it has a empty body. I also hit the breakpoint in the Screen1ViewBase::Screen1ViewBase() method, this method contains the ui box setting (position, color and an add method).

I don't understand what you mean for LTDC/DSI interrupt handlers. If you refer to call the OSWrappers::signalVSync(), yes, i have done a timer interrupt that fire at about 40Hz, and when it fire I hit the breakpoint placed on the OSWrappers::signalVSync() method.

[Martin KJELDSEN]

Just to be sure - You're working with STM32L496G-DISCO? Maybe you could get some inspiration from the L4R9I-DISCO application template from the designer. What struct me is that you're signaling signalVsync() using a timer instead of using the signals from the display controller. In the L4R9 AT we're signaling signalVSync() using

void HAL_DSI_TearingEffectCallback(DSI_HandleTypeDef* hdsi)

/Martin

[Luca1]

No, i'm working with a Nucleo-F767ZI and a display with RA8876 controller, this display.

I referred tho the STM32L496G-DISCO because this board have an application example suggest by the documentation of TouchGFX.

In my case there are an interrupt that signal the Teating Effect, but I don't use this at this moment because after this interrupt fire, I need to clear the interrupt flag.

I can clear this flag after the framebuffer is flushed, and at this moment i don't know how to do this. So i used an timer interrupt to simulate the Tearing Effect, as suggest by TouchGFX documentation.

NB, i know the limit of my display using the Nucleo F767ZI!

[Martin KJELDSEN]

Ah, that makes more sense.

Did you try debugging? What's the application doing when you pause it? f you're breaking inside your screens then the timer is doing its job

/Martin

[Luca1]

Yes i try to debugging! But is not simple to follow the code.

This is the call stack of the application when i pause it:

[Martin KJELDSEN]

This is a 1bpp application? (LCD1).

Looks like its blocked trying to take a lock the farmebuffer.

[Luca1]

Yes this is 1bpp application. 

I recognize that I have done a mistake to buy this display. I bought it without know anything about the displays. After reading the TouchGFX documentation I realized that this display have a big resolution and a wrong interface to be usable with my Nucleo-F767ZI board. 

However I can change the interface from serial (at this moment the display use the SPI) to parallel (I need to study what is the best choise between 8080 and 6800 parallel interface) in this way i can solve one bottleneck, but I need an external hardware (sdramm shield) to manage the full colordepth of this display. 

For this reason, at the moment I use 1bpp GUI. In this way I can use two framebuffer with this colordepth and send the framebuffer at 60Hz framerate (I set-up the SPI to run at 41Mbit/s). 

My goal is to learn and understand how to design and run an application GUI for the microcontroller, so for now 1bpp GUI it's sufficient to reach my goal.

If I terminate this first step, I will change the display interface from serial to parallel and I will design an application at 6bpp, because this is the maximum colordepth that I can use with my Nucleo-F767ZI board.

Yes it seem blocked but i don't know why.. Can you tell me if I miss to implements something or maybe i have done some wrong setting?

[Luca1]

Any help?