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Louis Cloete work
Associate III
December 3, 2021
Question

STM32L476 TouchGFX performance with 2.4" touch screen concurrently with other tasks

  • December 3, 2021
  • 6 replies
  • 1907 views

I am becoming interested in TouchGFX, and I want to know how it performs on STM32L476 for a 2.4" 240x320 touch screen. The chip is already doing some other control tasks, mostly digital I/O and bitbang SPI to control other chips, and 2 UART control interfaces with SCPI commands. The UARTs are on DMA.

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6 replies

MM..1
Super User
December 3, 2021

Your L476 is memory less for 240x320 full framebuffer internaly. You dont write how interface you plan use SPI/FMC for LCD, but both this need more MCU power as ltdc controlled displays. And what you ask as performance ?

Louis Cloete work
Associate III
December 3, 2021

> Your L476 is memory less for 240x320 full framebuffer internaly.

What do you mean by that? Is the L476 RAM too small or is it enough?

> You dont write how interface you plan use SPI/FMC for LCD

FMC is Flexible Memory Controller?

> but both this need more MCU power as ltdc controlled displays

What is ltdc controlled displays?

> And what you ask as performance ?

I mean does it update the screen regularly enough or does it get laggy.

MM..1
Super User
December 3, 2021

Is too small 240x320x2 > 128k

FMC yes can be used to parallel drive LCD as 8080 ...

LTDC is display interface RGB HSYNC VSYNC or in advanced DSI, both is MCU offload poripherals do its job without MCU intervention... I mean Lxxx dont have it

Is laggy or perfect , based on used methods

Louis Cloete work
Associate III
December 3, 2021

Ok so I am looking at a screen which has this LCD controller built in: https://www.crystalfontz.com/controllers/Ilitek/ILI9341/ It has graphics RAM, so I can put some data in it. However, it will still need some kind of control interface. Can the FMC drive it? I don't want to use SPI, since the manufacturer warns it is extremely slow.

EDIT: I see you already said FMC can drive LCD above.