Webinar: Low cost GUI solution with TouchGFX Q&A part 2

[Soren Myllerup MIKKELSEN]

Q&A session from webinar "Low cost GUI solution with TouchGFX"

One key trick of low RAM usage is using partial frame buffer, but what's the main limitation of this technique? What about updating a large part of the screen? Thank you

It is indeed the main limitation of this technique ! The larger the screen area to update the more steps are needed to render it whe using a too small partial frame buffer, see : https://support.touchgfx.com/docs/development/scenarios/lowering-memory-usage-with-partial-framebuffer/#configuring-partial-frame-buffers

is there a way to rotate images

Yes either statically when importing the image (Image panel) or dynamically but this will use intensively the CPU as rotation is curently not supported by any hardware IP (DMA2D or LTDC), see : https://support.touchgfx.com/docs/basic-concepts/performance/#the-complexity-of-rendering-the-pixels

How to use/edit a TouchGFX project, when a hex file of a project is available.

It is not possible to edit the application from HEX file only. You need source code of the project.

I have STM32H745 Discovery board.It is not in the appplication template. IT is very similar with H750 . How can i solve this?

For the time being the STM32H745 does not come with an application template indeed, and TouchGFX Generator does not yet support dual-core platform in general, sorry for the inconvenience.

Do you have plans to add support for themes so we can develop user interfaces with different themes (dark, light, high contrast...) without the need of redefining all the actions for all the screens in all the themes?

Some dark/light themes are already proposed in the Designer tool but it is limited to a given set of widgets, it is up to customers to define their own set of bitmaps for a given theme, the help of partners sucha as Mjolner can make sense in this case

any support for epaper displays?

Yes, see https://support.touchgfx.com/docs/development/hardware-selection/hardware-components/hardware-selection-display/#display-interface-overview

Is code generated by TouchGFX independent from IDE you are using?

You can choose one the following IDE's: Keil, IAR, STM32CubeIDE or create makefile

Thanks - will there be any application notes to help us implement with our own hardware? I am finding it difficult to get the paths correct. Also how about changing from SPI to parallel interface etc?

For sure that is the most tricky part, since we cannot test each an every displays we can only guide customers by providing application templates for each interface (LTDC, LTDC-DSI, SPI, FMC) and some articles : https://support.touchgfx.com/docs/development/touchgfx-hal-development/scenarios/scenarios-ltdc-parallel-rgb

and https://support.touchgfx.com/docs/development/touchgfx-hal-development/scenarios/scenarios-fmc

is it possibile to get a similar result with a ST7789 driver display instead of the ili9341 driver where where we have a TE interrupt pin?

This is a completely different use case, the TE pin of a display allows the MCU to identify the blanking period during which the display buffer can be refreshed (frame rendering) without causing visual artifacts, this would then replace the simple timer interrupt that is used on G0 to trigger the frame rendering.

1. Is the ToughGFX designer available for Linux? Are there any plans to do that?

No and no plan for the moment

Does TouchGFX generated code use dynamic memory allocation (new/delete) or will it work with statically allocated memory solely?

Yes TouchGFX does some dynamic memory allocation but only within a buffer whose size is defined at compilation stage.

With a screen change the screen is visibly updated from right to left on the real display. Is it also possible to set the update to be from left to right?

The way the screen is refreshed, pixel-per-pixel is driven by the display itself, not by the graphic library.

Thank you for your presentation. I would like to know which is the way you recommend to implement graphics that are personalized. Which are the best graphic formats on your system to optimize file size?

This is a wide question, in general, do not go for RGB888, most of the time RGB565 is sufficient and occupies less memory, then Look-up table format such as L8 or L4 can also drastically reduce bitmap size but will also limit the number of colors, for a better understanding of color formats, see : https://support.touchgfx.com/docs/basic-concepts/color-formats/

How do you synchronize the display update, i.e. the partial frame buffer update with the TE output of the display to avoid any tearing effect? Thx.

There is OSWrapper mechanism which define timeframe for framebuffer update. It could be fitted individualy to your display signals like TE pin.

Perhaps I have missed it, but is AC6 workbench no longer supported?

Yes, STM32CubeIDE replaces AC6.

I want ask you about implement our low level display driver for my circel display.Which interface i have to implement for use touchFx Gui?

It depends on the interface of your display, could be LTDC then the L4R9Discovery applicaton template can be a source of inspiration

Can TouchGFX be used with the 32F746GDISCOVERY kit?

Yes, it can. TouchGFX designer includes aplication template for this board.

Where can I get this board from in Germany?

You can obtain any STM32 boards from ST eStore or from our distribution partners. There is always a reference to their stores directly in the product page of given board on st.com

Touch interface - does the GUI design tool support a touch interface (with a different processor if necessary)?

Yes, it support touch functionality. Most of the touch interfaces use I2C communication. So, it is not problem to add it to project.

does it support svg image format ?

No, only PNG format is supported and more generally only rasterized format, no vector graphics ones

3. why do you use 3 blocks in this example for the parital framebuffer? Does it make a difference if 3x1920bytes or 1x5760bytes are used?

This is the default recommended size, 3 block of 3 lines of the maximum width/height, other values can be used depending on this maximum size and number of display area that must be refreshed at the same time. If your interface only contains a 20x20 block that changes over time you can define partial frame buffer as 1 block of 20x20x2 (16bits) size

is there support (planned) for round displays

Yes, the 32L4R9IDISCOVERY development Kit has a round display and a dedicated application template, TouchGFX does not care about it, as soon as the chosen MCU supports a display, TouchGFX will handle it

X-NUCLEO-GFX01M1 and NUCLEO-F446RE: External Loader.

Can you provide source code for MX25L6433F_STM32G071B_NUCLEO.stldr (STM32CubeIDE Project)

This should be possible, log a ticket on the Online support portal : https://my.st.com/ols#/ols/

Is it possible to use external RAM to expand the frame buffer?

Sure. If STM32 device supports connection of external RAM (FMC, OSPI ...), then you can use the location for framebuffer.

I fear there is no chance to use partial frame buffers and TouchGFX in an application in which we have a video stream in the background behind the widgets?

The rendering performances will be strongly impacted, partial frame buffer strategy is not for this purpose (full screen refresh here)

1/What is the best way to give informations (like température adjust) to an other task like an aumated task?

Usually using RTOS message queueing system from the model, see MVP design pattern : https://support.touchgfx.com/docs/development/ui-development/software-architecture/model-view-presenter-design-pattern/

How can the SPI Flash used? Do we need an external loader to add the capability to load the graphic into it? Is there an application note for this?

Indeed you need an external loader in this case, a MooC is dedicated to that, see : https://www.youtube.com/watch?v=YFIvJVsvIsE

Hello, if I would like to use multi-language messages, I saw in the documentation that we can create an excel file with all the strings, how does it work with chinese or cyrillic strings? Are all the symbols stored as bitmap in flash memory? (or external memory)?

For multi-language all translations are stored in the Excel file, this is done transparently by the tool using the proper font in the Designer. In the end yes all symbols are converted into glyphs and stored in external FLASH. Note that only the characters actually used are converted and stored, not systematically the complete list of symbols of a given font, see : https://support.touchgfx.com/docs/development/ui-development/touchgfx-engine-features/texts-and-fonts/

For examples for the G0, does one of the IDE's, have more to choose from ?

Yes the ST ecosystem support IAR, Keil and STM32CubeIDE

Are there drivers fo other LCD drivers apart from the ST LCd board?

Only for the ones embedded in the ST Developement Kits (Discovery or evaluation kits), see "HW Tools & Reference Designs" in : https://www.st.com/content/st_com/en/stm32-graphic-user-interface.html

Is it possible to use TouchGFX with displays as Bridgetek ME813-WH50C or similar?

As long as the display can be driven by one of our MCU (supported interface, supported pixel clock) it will be supported by TouchGFX

[Soren Myllerup MIKKELSEN]

Video can be found here: https://www.st.com/content/st_com/en/about/events/events.html/low-end-graphics-webinar.html