STEmWin not Displaying but LTDC Works

[Zach Neveu]

Posted on October 10, 2017 at 19:33

I am using an STM32F439BIT processor and developing in Keil uVision 5.  My goal is to make a touchscreen GUI for a VGA resolution touchscreen.  I have implemented STEmWin to the best of my abilities, using the LIN32 Driver (which should work with my touchscreen).  Using the hltdc.Init.Backcolor.Red/Green/Blue elements in LCD_LL_Init() I am able to set a solid color to the screen.  When I begin calling STEmWin functions (GUI_Clear(), GUI_DispStringAt(), etc.), nothing is printed to the screen.

Has anyone experienced this?  Anyone have insight into some common causes for this or what I may have missed?

Thanks!

#gui #display #touchscreen #stemwin

[Vangelis Fortounas]

Posted on October 11, 2017 at 17:21

Hello!

did you enabled CRC module? Its essential to work the driver.

[Zach Neveu]

Posted on October 11, 2017 at 18:39

HAL_CRC_MODULE_ENABLED is defined in stm32f4xx_hal_conf.h, and __HAL_RCC_CRC_CLK_ENABLE() is called before any GUI functions are called, so yes, I believe the CRC module should be enabled.  Is there anything else you can think of that may be causing the problem?

Thanks for your help!

[Vangelis Fortounas]

Posted on October 11, 2017 at 18:57

Which LCD type you use?

LIN driver is for direct access to video memory only

GUI functions like GUI_DispStringAt use commands also , like SetWindowSize .

[Zach Neveu]

Posted on October 11, 2017 at 19:58

The LCD is a UMSH-8247MD-15T from URT.  It uses an 18 bit parallel color interface, and matches up with the LTDC interface on the processor.  Using the LTDC functions provided in the HAL I am able to get the screen to work.  A previous project of mine involved a STM32f4xx Eval board with a touchscreen with a very similar interface and the LIN driver worked with that.  What exactly is meant by video memory? I haven't been able to get a good explanation of where video memory is located/what accesses it etc.

Thanks!