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Associate
Aug 22, 2026 12:36 PM UTC
Solved

Struggling with TouchGFX on custom board

I am struggling to get TouchGFX running on my custom board. The processor is the STM32H7A3RGT and I am driving a 320 pixel x 960 pixel LCD display. I have allocated a frame buffer in internal RAM and have LTDC producing PCLK, DE, VSYNC and HSYNC. I have configured my firmware using CubeMX to use FreeRTOS. I added a call to MX_TouchGFX_Process in my default task but it gets stuck on an assert. Specifically here:

Call Stack

The reason it gets stuck is because pxQueue->ixItemSize is not zero !

ASSERT in xQueueSemaphoreTake

What am I missing ?

Andy

AndyFraserBest answer
Associate
Aug 22, 2026 3:34 PM UTC

Not sure what I have done but it is no longer getting stuck and am now getting an image on my LCD 😁 (sort of 😦).

Andy

12 replies

MM..1
Super User
Aug 22, 2026 1:26 PM UTC

Check in MX NVIC interrupt settings for all hw … Next in MX TouchGFX check your setup is LTDC for type and for timing.

Associate
Aug 22, 2026 1:40 PM UTC

Thanks for the reply - what specifically am I looking for in NVIC?

I have configured everything for LTDC and am seeing what looks like good signals on PCLK (10MHz), DE, VSYNC and HSYNC.

This looks more like a firmware issue in that xQueueSemaphoreTake is expecting an item size of 0 and the item size is 320.

Looking at the stack trace, it looks like TouchGFX is trying to ‘blit’ to the frame buffer and I am suspicious about the 320 as that is the width of my display in pixels.

Andy

MM..1
Super User
Aug 22, 2026 3:05 PM UTC

Show TouchGFX settings in MX too.

Associate
Sep 1, 2026 2:38 PM UTC

Yes, it is working fine now - can’t exactly remember what the solution was though :-(

 

Andy

Associate
Sep 25, 2026 9:45 PM UTC

Actually, seems my issue has not resolved itself :-(

I made a few changes to my board and created a new CubeMX project, transferred all the settings relating to LTDC, TouchGfx and FreeRTOS and I am back to seeing the same problem where it get stuck:

 

Again, you can see that it asserts because uxItemSize is not zero.

I don’t know how I managed to fix it on the previous board.

Andy

MM..1
Super User
Sep 26, 2026 10:48 AM UTC

Maybe old MX bug. After new project first generate was not complete… Repaet open ioc and try second generate.
Or your GUI task require bigger stack setings