Hello, i need a microcontroller which supports an 800x800 display. Can you tell me the main products of the family F4 or F7 (or maybe H7) that supports this?

[AMerc.4]

..

[waclawek.jan]

Probably all STM32 with LTDC can support that resolution in *some* configuration - but you might be disappointed by that configuration and also the resulting constraints on what else the mcu can do.

Read AN4861, concentrate perhaps on the subchapter dealing with "bandwidth requirements".

JW

[berendi]

Find the required pixel clock frequency​ in the display datasheet, and calculate the memory requirements. What colour resolution should the application support? 4/8/16/24 bits/pixel?

[AMerc.4]

Minimum requirement 16 bit, better if 24. The display should be this:

https://www.displaymodule.com/products/dm-tftr34-359

I don't know if link it with SPI or with HDMI to MIPI DSI. What do you suggests?

[berendi]

> Minimum requirement 16 bit, better if 24.

Now you can calculate the memory requirement.

Then find the pixel clock frequency in the datasheet to calculate the bandwidth.

> I don't know if link it with SPI or with HDMI to MIPI DSI. 

Does it have a SPI interface? What is it for?

[waclawek.jan]

MIPI DSI in the STM32 have only 2 lanes (the display you've linked to requires 3).

Have you read AN4861 already?

You may be better off using something more user-friendly, such as the Rasberry-Pi.

JW

[AMerc.4]

Unfortunately i need this for an electric bike. I need fast boot time, just what Raspberry doesn't have.

I read AN4861, 800x800 have a total of 640000 pixels, the microcontroller support up to 921600 pixels. Since i want 24bit color, my framebuffer should be around 2000 Kbytes, right?

Tell me if i'm wrong.

[waclawek.jan]

Yes this portion of the math is right. Now, the question is, what sort of memory would you use, and whether any STM32 would be able to move those 2Mbytes out of that memory and into the LCD, each frame, i.e. some 50x per second. That is, without the processor writing anything into that memory, i.e. a static, never changing picture.

And I've already said, that particular display you've given link to, is a 3-lane MIPI, STM32s support only 2.

JW

[AMerc.4]

Don't worry about display interface. Because i can have different displays or different connectors, such an HDMI to MIPI 3 lines, and in STM32 side i put an HDMI to MIPI 2 lines. Or if you can suggest me some other solution, such as a display with RGB protocol and so on.

I'm very noob about this board. Do i need a storage for my GUI? I imagined something like Arduino, in which all the program is memorized locally.

[berendi]

We could suggest you something if we knew your requirements.

You've selected a fancy display which doesn't even have a proper datasheet with basic timing information. And that's about all we know. Until we know more, much more, and don't do your homework, there will be only questions.

What do you think, why does the display module require three lanes, for fun? Because two lanes can't provide the data fast enough for its pixel clock, whatever it is. Even if you convert two lanes to HDMI and then back to MIPI, it won't solve the bottleneck.

Now you have the size of the framebuffer. Knowing the refresh rate allowed by the display, we could estimate the required memory bandwidth, then have an idea what kind external memory can do that, if any.

How could we know whether you need extra flash for your GUI? Depending on the amount of graphics you want to display, a few kilobytes to several gigabytes. Do you have an idea how much memory does your graphics require?

Have you seen at least one STM32 datasheet, or at least the product webpage? Do they have internal flash storage? How much? Would it cover your needs? Have you found the product selector?