How setenv vidargs Colibri iMX6ULL RGB24 display AZ ATM0430D12M, 480 x 272?

Technical Support
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The display interface appears common. 40-pin RGB24 TFT LCD.

I am trying trial an error vidargs using snippets I find on developer.toradex.com

I am using the Qt E-Bike Demo image. Maybe this will not work at resolutions below 640x480?

Steps Taken

  1. Disconnect VGA port that worked
    with E-Bike Demo. I tested down to 640x480
    (setenv vidargs
    video='mxsfb:640x480M-16@60)
  2. With power-off, connect AZ ATM0430D12M, 480 x 272, RGB24 to X34 Unified TFT Interface
  3. U-boot using following vidargs:
  • setenv vidargs video='mxcfb0:480x272M-16@60,if=RGB24’

  1. Kernel starts according to u-boot terminal

  2. Display remains black, no flickering, nothing.

    setenv vidargs video='mxcfb0:480x272M-16@60,if=RGB24’

  • Is frame buffer name correct?
  • bpp ?
  • Refresh freq?

Any tips or suggestions are much appreciated.

Thanks in advance,

-Ed

References:

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Hi @embeddedEd

I quickly checked the datasheet of the display and it looks like they don’t exactly use the Unified Display Interface but a slightly changed version. I guess you would need some kind of converter circuit to make it work with our Evaluation Board.
See: https://docs.toradex.com/100069-iris-datasheet.pdf Section 3.7.2
And https://www.azdisplays.com/PDF/ATM0430D12M.pdf Section 2

The iMX6ULL has a different naming for the video device:

setenv vidargs video='mxsfb:480x272M-16@60'

See Display Output, Resolution and Timings (Linux) | Toradex Developer Center.

Maybe you would also have to add the resolution to the devicetree file, because it is unusual. We explain that in the same article.

I think the Qt application should be shown on a display with this resolution. It normally scales pretty well.

Regards,
Stefan

3

@stefan_e.tx Thank you for the great info!

I put the Unified Display Interface versus AZ ATM0430D12M pin-out in a spreadsheet in side-by-side columns and I understand what you mean.

I may just purchase one of 480 x 272 displays listed on your Supported Displays page to save time from having to create a generic RGB adapter adapter board.

Thank you for pointing out the naming used by the iMX6ULL and timing / devicetree info.

At this point I mainly want to see how the Qt E-Bike demo scales down to 480 x 272 and investigate if demo source is available and if UI could be tweaked for a mockup prototype.

I am trying to figure out if Linux can handle generation of low-latency streaming audio that depends on an analog input and updates a UI widget such as a meter or signal-level bar. Similar to a geiger counter or a metal detector device.

Thanks again!