Guidance regarding using LTDC Controller in STM32L4R5ZI based Nucleo Board.

Yogeshk · ‎2020-05-10

We are in the initial evaluation stage of using the STM32L5R5ZI module for a custom board we are planning to build for an Engine Panel. Part of the Engine panel is also a LCD-TFT touch screen that we are hoping to drive using the built in LTDC controller which is part of this STM32 Module.

1) Are there any examples/tutorial for this module on how to configure the LTDC Controller and to drive the LCD-TFT especially a touch screen one?

2) One of the questions I had around while configuring the GPIO pins on the Nucleo board that supports this L4R5ZI module was, can we use any of the GPIO pins for the HSYNC, VSYNC, DE, LCD_CLK, and the RGB related pins or can we only choose GPIO pins that have been designated to have alternate functions for ex: LCD_HSYNC, LCD_VSYNC, LCD_CLK etc?

3) Also it seems like lot of the other settings around configuring the Clock frequencies, and other LTDC related settings are driven by the settings called out in the data sheet of the Display device of our choice. Is there any guidance as to how we need to tie/map those settings in the data sheet to the corresponding settings in the LTDC?

Thanks,

Yogesh

AME MCU Support Center BB · ‎2020-05-14

By the way, STM32L4R5ZI devices don't have the LTDC peripheral (LCD_TFT) - Refer to Table 2

https://www.st.com/resource/en/datasheet/stm32l4r5zi.pdf

Yogeshk · ‎2020-05-17

I am confused, in the features it says the STM32L4R5ZI following regarding the Graphics related features. Does the presence of an LCD-TFT controller not mean it supports LTDC? Also if we want to use these board to eventually drive a 24 bit display, how could we use the LCD-TFT controller to achieve the same as the LTDC?

Advanced graphics features

Chrom-ART Accelerator (DMA2D) for enhanced graphic content creation
Chrom-GRC (GFXMMU) allowing up to 20% of graphic resources optimization
MIPI® DSI Host controller with two DSI lanes running at up to 500 Mbits/s each
LCD-TFT controller

Thanks,

Yogesh

Yogeshk · ‎2020-05-18

It is extremely misleading that on the stm32L4R5ZI product page under key features its list out as shown below. It should be clearly called out on the product page the only thing it supports under graphics feature is chrom-art accelerator and not the other three listed out.

https://www.st.com/en/microcontrollers-microprocessors/stm32l4r5zi.html

Advanced graphics features

Chrom-ART Accelerator (DMA2D) for enhanced graphic content creation
Chrom-GRC (GFXMMU) allowing up to 20% of graphic resources optimization
MIPI® DSI Host controller with two DSI lanes running at up to 500 Mbits/s each
LCD-TFT controller

Thanks,

Yogesh

Martin KJELDSEN · ‎2020-05-19

While it does specifically say "Ultra-low-power with FPU ARM Cortex-M4 MCU 120 MHz with 2048 kbytes Flash, USB OTG, DFSDM, CHROM-ART" for L4R5 i agree that also having a description for a _family_ that lists the collective features for that family can seem confusing!

/Martin