How to use touchgfx with nucleo board that is not in standard list also how to use a display controller like ili9488 or RA8875.

[Kyrpav]

Hi i am very new to all stm32, i have some project that i want to move to stm32 mcus. I would like to know if i have a nucleo board that is not in the list of selections that exist in designer, or i have selected an mcu that a dev board does not exist at all like H755ZI what should i select as board. Also about screens until now i have used 2 controllers ili9488 and RA8875 for larger resolution, how this can be used since the discovery boards have other displays that do not specify what they are, and how all these things can be fixed with touchgfx. Is there any guide that explains these cases that i could read?

[HP]

It is a complicated setup - but rewarding when you manage to get it working :)

I have only worked with one SPI display for which I didn't have to write the pixel-pushing method.

I would go with a display like https://www.buydisplay.com/7-tft-lcd-touch-screen-display-module-800x480-for-mp4-gps-tablet-pc

that's RGB out of the box. you only need to porch settings to get it working.

The LTDC module in the STM32 can handle all the pixel-pushing for you so that's easier to start with.

Good luck and welcome ;)

[Kyrpav]

thank you for the proposal i assume that if i setup the RA8875 for RGB to uses the R[],G[],B[] pins then i should have the same exact result. and the pixel-pushing is the same.

I was just a bit curious watching the Software packs component selector in CubeMX and you go to install x-CUBE-DISPLAY if you open the setting that they have with the arrow it shows ILI9341 and ST7789V so it is confusing about what to set and from where which options have to be selected.

[HP]

Yeah, if you configure for RGB you can easily use the LTDC (I would imagine)

I never tried the x-CUBE package you mention since I always managed to find a solution with RGB displays.

I do know that support for other displays than parallel and DSI was.... lacking some time ago so the display package might make up for that :)

[Kyrpav]

i have to cover tones of things it seems. thank you for your help i will try to check all.

[MM..1]

Yes primary you need understand, that STM connects displays directly and no over man in the middle RA8875. You can solder neverending and only It supports 8080 6800 8-bit,16-bit parallel,3-wire,4-wire,I2C serial spi interface. No RGB , what is LTDC direct interface.

Try other way end. Define what you need:

A. Static slow GUI ... SPI RA and other bridged can use TochGFX partial buffering

B. Smooth animated GUI

Define resolution not inches...

For example STM32F469 can smoothly drive 1280x480 DSI MIPI 2lanes.

[Kyrpav]

From what you say i understand that i had wrong impression. I thought that display with 8 pins per colour support RGB interface and this is how this works like

5~12 R0~R7 Red Data

13~20 G0~G7 Green Data

21~28 B0~B7 Blue Data

From the display that you send.

I thought that RA8875 had the same but it has DB0-DB15 for Data bus which i suppose it is different thing.

I also need to understand DSI and MIPI :tired_face:

[MM..1]

Simply your RA is wwaste IC create connection 1. MCU -> 2. RA (mcu2) -> 3.DRV LCD (S77....) -> LCD , this is designed for MCU with low power and ram.

STM produce around hundrets nucleos and 100x more MCUs STM32 and all with min requirments is capable drive displays+TGFX without 2.RA boards

[Kyrpav]

SO i could use what ever RGB TFT screen with LTDC, and the discovery board uses a DSI MIPI display which means that i could pick the schematics as you did in your screen and use whatever IPS screen i could find that supports DSI MIPI(in that case it is better to user QuadSPi with external SDRAM)?Also DSI MIPI has a specific pin order (header setup)?

[MM..1]

DSI is used only on boards, that have it in STM internaly. DSI is LTDC to DSI bridge internal.

External QSPI is only required when internal is low. SDRAM is strict for displays with big resolutions. For example F469 have internal 320kB then you can place here 1024x320 L8 single framebuffer. Every better(RGB565...double buffer ...) need external SDRAM.

[Kyrpav]

Which if i understand well you never setup DSI just LTDC? so the pins to be set is just the ltdc and then you are connecting the display to DSI (i have to learn also about ltdc which pins are required though) .

For displays that are 800x480 or more you need SDRAM as you show in your video to have bigger buffer? and not to use the STM32 memory?

Am i correct and where i am not?