BRT Community

Hi Rudolph,

The new EAB and the associated extensions are currently being completed and should be available by end-September. We'll keep you updated here,

Best Regards, BRT Community

Hello kumaichi,

Thank you for your post.

It is certainly a curious issue in relation to the FreeRTOS implementation.

I would be interested to know whether moving the REG_PWM_DUTY call to either of the indicated places below  results in different behaviour:

    TFT_qspi_cmd_setrotate(0);

    TFT_qspi_write16(REG_GPIOX_DIR, 0xFFFF);
    TFT_qspi_write16(REG_GPIOX, 0xFFFF);

        <---------------------- TO HERE

    /* after this display is visible on the LCD */
    TFT_qspi_write8(REG_PCLK, DispPCLK);

    //while (TFT_busy() != E_OK){};
    TFT_qspi_WaitCmdfifo_empty();

    /* If the status of the flash is 0 (INIT) Attach it */
    while (EVE_FLASH_STATUS_DETACHED == TFT_qspi_read8(REG_FLASH_STATUS))
    {
        TFT_qspi_dl_cmd(CMD_FLASHATTACH);
    }

    /* Initialize the onboard flash and put in FAST mode
    * Need to check the return value and not proceed if
    * there is an error so we can read in the Fonts
    */
    if (TFT_init_flash() == E_OK)
    {
        /* Read the image from the flash */
        uint32_t flashCommands[] =
        {
                CMD_FLASHREAD, (uint32_t) MEM_FONT34, (uint32_t) 198592, (uint32_t) 280 + 40,
                CMD_FLASHREAD, (uint32_t) CAR_IMAGE_HORIZONTAL, (uint32_t) 198912, (uint32_t) 92000 + 32
        };

        TFT_qspi_cmd_burst(flashCommands,    sizeof(flashCommands) / sizeof(flashCommands[0]));

        while (TFT_busy() != E_OK)
        {
        };

        TFT_qspi_WaitCmdfifo_empty();
    }

        <---------------------- OR HERE

    TFT_qspi_dl_cmd(CMD_DLSTART);
    TFT_qspi_dl_cmd(DL_CLEAR_COLOR_RGB | WHITE);
    TFT_qspi_dl_cmd(DL_CLEAR | CLR_COL | CLR_STN | CLR_TAG);
    TFT_qspi_dl_cmd(DL_BEGIN);

    TFT_qspi_dl_cmd(COLOR_RGB(120, 6, 6));

    TFT_qspi_cmd_setfont2(13, MEM_FONT34, 0); /* assign bitmap handle to a custom font */
    TFT_qspi_cmd_text((DispWidth / 2), (DispHeight / 5) - 15, 13, EVE_OPT_CENTERX, "Please wait...");

    TFT_qspi_dl_cmd(COLOR_RGB(20, 20, 130));

    TFT_qspi_cmd_spinner(DispWidth / 2, DispHeight / 2, 0, 0);

    //TFT_qspi_write8(REG_PWM_DUTY, 25); 

i.e. is it specifically this call causing the issue, or is just where the call is being executed in the sequence of SPI writes that is the problem.

Can i ask if you are observing the write taking place on the SPI bus when the issue occurs?


Best Regards,
BRT Community

Hi Rudolph,

Glad that you like the new extensions. We'll check when the new EAB will be released and will post back here with an update very soon,

Best Regards, BRT Community

Hello,

Could we check which model of EVE chip you are using with your font?

Also, which EAB conversion settings and which application SetFont2 code were you using to set up your font?

Best Regards, BRT Community

Hi Nick,

Thanks for posting your findings, our R&D team are currently checking on this and we'll post a reply very soon,

Best Regards, BRT Community

Hi Rudolph,

We use an HDMI to LVDS board here for testing too, you can find details of the board that we use in chapter 9 of this new application note below,

https://brtchip.com/wp-content/uploads/2025/06/BRT_AN_092-BT820-Hardware-Design-Example.pdf

You can use a camera with HDMI output or even a laptop with HDMI monitor output to input video to the BT820B,

Best Regards, BRT Community

Hi Maria,

To get your touch working, we recommend to use the CMD_SETROTATE instead of the register write. The command writes the REG_ROTATE register for you but also does the touch rotation.

If you calibrate your touchscreen after start-up and then use the command, this will rotate your touch as well as your graphics, and so the touch will work well across the full screen.


Best Regards, BRT Community



 

Hi Rudolph, Maria,
 
Thanks for your inputs on these items, please note that there will be some integrated modules coming soon for BT820B and so we'll keep you posted here.
 
Hi Matrix Orbital,
 
We have to say, the ability to make a stunning full-colour touch-enabled GUI on an LVDS 15.6" panel with high-resolution images and fonts, touch icons overlaid and live video (with pre-processing) driven by some very cost-effective MCUs is really quite impressive.
 
Our new BT820B combines the many benefits of our earlier EVE devices (including their graphics, touch and audio capability) with even more powerful graphics capabilities.
- Directly drive large LVDS panels up to 1920 x 1200 e.g. 15.6" panels
- Use high-resolution live video in your UI easily, and without it passing through the MCU
- Pre-processing to add effects and improve the video stream without MCU workload
- The ability to render very complex graphics by combining the above with a frame buffer
- and many more...
 
These make the BT820B ideal for all kinds of products and applications embracing the latest UI trends including large hi-res displays, more complex UIs with lots of waveforms and controls, and in some cases live video etc.   The BT820B is therefore ideal for both new product designs and existing EVE designs being updated.

Best Regards, BRT Community

Hi Nick,

Great to hear that you have your PCB designed.

There are a few different development approaches that you can use.

EVE Screen Designer will allow you to lay out the user interface via the drag-and-drop editor. The latest ESD versions have STM32 CUBE IDE export also included and so you can choose the STM32 as the platform in ESD. You can then export to an STM32 CUBE IDE project via the menu and then build on CUE IDE. ESD also includes the flowchart based programming of the application flow. For this reason, the ESD project typically runs on the MCU as the main program loop and interaction with other I/O on the MCU can for example be added via User code in ESD. One example is the Blink LED via GPIO example where a GPIO on the MCU is controlled and the usercode example.

Another option is a code-based solution such as our code examples from https://github.com/Bridgetek/ or Rudolph's library. If you require a lot of editing on a pixel by pixel basis this may be a good solution. You can update things like raw bitmaps in RAM_G and they will be reflected on the screen. We also have different bitmap formats such as the bargraph type which may be useful. For the code-based solution, you can also use EVE Screen Editor to lay out your user interface, and then copy the list of commands into your code and this will make the layout easier.

What kind of spectrograms and graphs will you be using, and we can see if we have any examples for either ESD or for a code-based application?

Best Regards, BRT Community

Hello Rudolph,

Thank you for this!

We have a Seleae Logic analyser here in the office so we will try out these high level analysers when we get a chance!
In any case these look really useful for any EVE users debugging needs.

Best Regards,
BRT Community

Hello,

Thank you for your post.

I will enquire with the software team to see if they have a document which covers the C prototypes for each support EVE command.

Best Regards,
BRT Community

Hello,

we'd like to offer the following explanations and suggestions:
1. Mismatch in RGB Bit Depth (OUTBITS Setting)
Some LCD panels, although labeled as supporting RGB888 (24-bit), may internally operate using RGB666 (18-bit). If the EVE IC's output bit setting does not match the actual bit depth supported by the display, it can lead to color distortion or visual artifacts such as noise lines.
Suggestion:
Please verify your LCD panel's actual color depth and ensure that the REG_OUTBITS register is configured appropriately during initialization to match the panel.

2. Avoid Using CMD_GRADIENT for Red-Sensitive Precision Areas
CMD_GRADIENT uses internal linear interpolation. In high-contrast or precision-sensitive areas—such as gradients involving red—it is prone to rounding errors that may cause visible banding or fine lines.
Suggestion:
Consider using a custom gradient image (bitmap) instead, and load it into RAM or flash to ensure consistent rendering and avoid interpolation artifacts.

3. Fine-Tune the Gradient End Color & Refresh the Cache
Using red values like 0xFF0000 (full red) can fall on edge-case transitions in RGB666 mode, leading to visual inconsistencies.
Suggestion:
Try slightly dimming the gradient end color—for example, use 0xF00000 instead of 0xFF0000—and observe whether the black line still appears.
Also, try calling CMD_CLEARCACHE() to clear the on-chip bitmap cache, which may help eliminate any residual rendering artifacts.

Best Regards,
BRT Community

Hi Rudolph,

Sorry for the delayed reply, Our new Programmers guide will be ready soon,

You are correct, the LVDS output is for one display only. We use two channels to allow us to support the high resolution panels such as 1920 x 1200, but the two channels work together to provide the bandwidth required. Therefore, they are not designed to support two separate display panels on one BT820B IC.

Best Regards, BRT Community

Hi,

Thanks for your question,

We'll check with our R&D team on this and will let you know as soon as possible,

Best Regards, BRT Community

Hello,

Thank you for the update.

In cases where the SPI connection is long and there is no possibility to shorten it significantly, we would normally suggest adjusting the slew rate and drive strength characteristics of the MCU SPI port to help improve transmission quality. But please do keep us updated with how your testing goes.

Best Regards,
BRT Community