Advice on buying a display for STM32F469 Discovery

[Maurizio1]

Hello.

I'm going to purchase a round AMOLED display to be used with a STM32F469 Discovery board.

This is my current candidate: PV13904PY24G.

This display has a resolution of 454x454 pixels. TouchGFX says STM32F4 is usable for displays up to 450x450 pixels. Is this display too big?

It's driven by RM69330, and I have the datasheet of this IC.

Before buying, I'll ask if they manufacturer has any kind of code example for any platform, so that I have some reference.

Do you see any problem in what I plan to do?

What will I need to propertly use this display with TouchGFX on the STM32F469 Discovery board?

Will I need or should I use other hardware to interface the display to the Discovery board or to get to know the display before actually connecting it to the board?

Is the touch data transmitted on a different interface?

This is my first experience in embedded development.

Thanks for advance for any advice you would like to give me.

[MM..1]

You need only one info , work display in two lanes MIPI DSI mode? When yes you can use it. Second trouble is connectors is same as on Discovery board?

When no your idea use discovery board need change to make custom board...

Touch data is transmitted on different interface ? YES.

[Tesla DeLorean · Accepted solution]

The display vendors typically can provide mechanicals and manuals for the display controller, don't expect them to supply or write code for a given platform. You'll want to review existing examples for the F4, L4, F7, etc platforms using similar controllers and interface methods. The LTDC and DSI have some plumbing you need to understand. There are App Notes.

You might want to consider the F769 board to bring up a DSI display, ST moved to a MICTOR header type arrangement to allow screens to be changed.

You have 2-lanes at 500 Mbps (1Gps) for the video content. the 454x454 should be well below the available bandwidth ceiling on the interface.

>>Do you see any problem in what I plan to do?

Technically no, but you've got a lot of moving parts you'll have to personally own.

https://www.st.com/resource/en/application_note/dm00287603-lcdtft-display-controller-ltdc-on-stm32-mcus-stmicroelectronics.pdf

https://www.st.com/resource/en/application_note/dm00287601-dsi-host-on-stm32f469479-stm32f7x8x9-and-stm32l4r9s9-mcus-stmicroelectronics.pdf

[Maurizio1]

Thanks for your answer, Tesla DeLorean.

I had already started to read AN4860. I thought LTDC (AN4861) was for driving controller-less displays via parallel RGB interface only. I'll look into it, anyway, since you say it's relevant to my case.

After reading your message, my greatest worry now is physically replacing the screen. I had a closer look at the Discovery, and I cannot understand how I am supposed to remove the screen without damaging the board.

I googled about replacing the display of both F469 and F769 board, but didn't find any report of that.

I take a lot of things for granted in this field.

I'll ask a question specifically about this step.

Probably a better route is just

1) draw a circular display on this board's rectangular display, and

2) develop a custom PCB.

Another possible route is using HDMI.

The display I want to use has an HDMI board, and ST sells a DSI to HDMI board, too: "It can be used on STM32 evaluation boards or discovery boards, to demonstrate video solutions based on STM32 MCUs."

On the other hand, the fact that ST sells this "DSI to HDMI" board that can be used with "discovery boards" means I should be able to detach the screen from STM32F469 without damaging it.

Thanks again!

[VLau]

Pay close attention to the connectors on the disco boards and the displays you're going to buy. It's likely you have to do adapter board by yourself.

DSI to HDMI board can be attached only to few disco boards (ex. 32F769IDISCOVERY) and I can't see how HDMI would help you.

[Maurizio1]

Thanks for pointing out that this DSI to HDMI board board only work with 32F769IDISCOVERY, VLau. Probably, it's my fault, but I don't see it specified anywhere in the web page nor in the documentation files. It's true that the only board linked in that page is 32F769IDISCOVERY, indeed.

I thought HDMI could help me because the manufacturer of the display provides an optional HDMI board to drive the display, as I mentioned. Or so say the the product page (where the HDMI board is also depicted) and the original page that I linked. But now the sales person is saying that there is no HDMI board.

So HDMI is not an option, anymore.

Thanks!

[Tesla DeLorean]

I think the HDMI interface would port to several of the L4 and H7 boards. The bandwidth is however limiting in ST's DSI implementations, just not capable of FHD or UHD

[MF35]

Hi Maurizio, I'm working with this display, and I'm struggling to make it show something...

have you, by any chance, start to work with it? BR. Fred