Corrupted TouchGFX text

[dave2012]

I have a TouchGFX application where Flex Button text is sometimes being corrupted as are TextArea widgets (both with and without Wildcards). Images remain unaffected. The processor is a STM32U599, display type is RGB888 LTDC based and no external FLASH graphic storage is used.

The corruption cannot be cleared with a processor hard reset, only power cycling clears it.

From the attached image, the two 't' characters in the corrupted "Start" text are the same so it appears that a RAM based font bitmap cache is being corrupted. If so, any ideas where to find the name of this structure/buffer and is it managed exclusively by the TouchGFX library code?

Thanks

 

[MM..1]

Is your issue after flash programming? I have same issues, but seems after power off - on all works. 

Yes affected is fonts seems all types, vector too, reported on other thread.

[GaetanGodart]

Hello @dave2012 ,

Is it a custom board or is it the STM32U599J-DK?

Where is your font stored? In internal memory?

Once you do the power cycling reset, it always works? So the issue only happens after flashing?

Regards,

[dave2012]

Hello Gaetan,

Yes, it's a custom board and the font is stored in internal FLASH.

The text corrution seems to happen in 2 scenarios:

1. While debugging in the IDE
2. After a firmware update which is done via a custom bootloader. The bootloader implements a simple single screen GUI with 8-bit colour which transfers execution to the newly programmed UI application (multiple screens, 24-bit).

So far, power cycling always resolves the issue but pressing reset in the IDE doesn't. I'm using the ST-LInk GDB server which I assume implements a hardware reset but maybe you could confirm?

Thanks
Dave

[dave2012 · Accepted solution]

If anyone else comes across this issue, it's caused by old data in DCACHE2 not being properly invalidated at startup. ST support came up with a fix to add to main.c (or dcache.c if generated code is split into multiple files):

/* USER CODE BEGIN DCACHE2_Init 2 */
// Ensure that GPU2D texture cache does not hold any out-dated data from previous application
__HAL_RCC_GPU2D_CLK_ENABLE();
HAL_DCACHE_Invalidate(&hdcache2);
/* USER CODE END DCACHE2_Init 2 */