Do I need an extension board for V-by-One?


Do I need an extension board for V-by-One video output?
Can I get some details?

The product details page of VIM4 never mentions about it.
At the " Quad Display Interfaces - HDMI, MIPI-DSI, V-by-One & eDP" section, it just says that “the number of independent displays will be limited by the OS”.

And, I asked couple of questions via Khadas homepage web chat, and got those answers.

For your question - Does it support V-by-One video output on linux and android?
→ yes but currently the port is not functional. We will release a special extension baord for it in Q2. Then the VB1 port will be full functional.

for your question - how can I configure V-by-One output framerate and resolution (both linux and android?
→ We will release some documents for it in Q2 I believe.

Then, asked one more question and no answer.
Okay. Thanks. BTW, I see that V-by-One ports already exist on VIM4. Why do I need an extension board for V-by-One?
→ ignored

So I am asking to the forum.
Hope to see some responses.

@windchaser Yes, V-by-One currently requires a small adapter board, which is already in our release plan

@Frank Can I get some details?

As I wrote, there’re V-by-One ports on VIM4. Why do I need an extra board?

@windchaser If you can find the V-by-One screen that corresponds to the pin, you don’t need to use a breakout board.

@Totti please help!!!

@Frank Thanks for the quick response! (And sorry for keep asking)

Does that mean that If I connect a V-by-One display panel then I can see VIM4 video out on it?

So, if I buy a panel like this - V-by-one Interface Innolux Brand 65 Inch Lcd Panel V650dj4-ks5 With Resolution 3840(rgb)x2160(uhd) - Buy 3840(rgb)*2160,Chimei 65inch Lcd Panel,V-by- One 8 Lane Interface Product on , I don’t need an extension board, right?
(Oops. Number of V-by-One pins are different but, please assume that the panel uses 30-pin V-by-One)

1/The V-by-One port on VIM4 was a 30 pins FPC connector and its pin definition is made by us;
2/There are many VBO screens on the market,something like 34 inches, 43 inches ,65 inches and so on;Their signal input connectors may or may not be the same;And their logic power input voltage may be different;
So you may need to make an extra board or FPC cable for VIM4 to connect the screens!

Thanks, @Totti
I asked a H/W expert about it and he said that he can deal with H/W things, like bridge board, pin maps, and FPC.
And also he mentioned that V-by-One is kind of market de-facto standard for display panels, so he didn’t have any issues with display panels and boards on his previous projects.

But, based on the response from Khadas, it seems like the V-by-One of VIM4 is not functional yet.
I wish you guys release S/W and documents soon! :slight_smile:

This version of firmware software supports VBO display by default. You can try. We have verified it. It can support HDMI + VBO dual screen display.

64 bit firmware is under development. It will be released later.

Thanks, @goenjoy
You convinced me. I’ve ordered couple of VIM4 to try out for my project :slight_smile:
Hope I can check the basic funtionalities before the official release of the source codes and the documents.

Thank you for your support, all Khadas team!

@windchaser 64bit SDK and firmware released.

Thanks again, @goenjoy !
I believe that you mentioned it here because V-by-One works on that firmware. :wink:
You guys are working hard, I know, and one last thing I’m waiting for is the documentaion about v-by-one configuration including resolution change, HDR setting, refresh rate, and so on.

Sorry, there is no relevant document about VBO at present. But I can tell you about the VBO dts configuration here:


The board VBO electrical connection is selected as follows: lcd1->vbyone_1
The yellow box indicates that you can configure VBO related parameters.
The default resolution of the code is 3840*2160.

That is awesome, @goenjoy

I will check it immediately after receiving the VIM4.
Unfortunately, the purchasing department says it takes a month for delivery. :cry:

Anyway, thousand of thanks!!

@goenjoy Have you been able to produce V-by-One documentation that can be used to find a suitable display?

The V-by-One pinout and connector type can be found in the schematics. But what about other documentation like:

  • which V-by-One standard is supported: original/HS/US?
  • image bit depth?
  • framerates supported?
  • pixel data order on the 8x VBO lanes?
  • purpose and functionality of the I2C also available in the connector?

Also, I assume that the pre-built 64bit Android 11 version that was released 221228 also supports VBO/V-by-One 4K out-of-the box?

I don’t quite understand what you mean. Or you can find the answer from these parameter settings.

yes. You can also get the answer through the hardware schematic or parameter settings.

The circuit design is effective. How to use it depends on the corresponding screen. The VBO screen on our hand does not use this I2C interface.


Thanks for your reply, I will try to clarify my questions. Due to forum limitations I have to split up my answer in multiple posts (as I am not allowed to have multiple links and image references as a new user).

I only have access to Amlogic A3111D2 specs in - Index of /products/vim4/datasheet/, where most of VBO information is missing. So I cannot cross-reference with VBO spec
Please correct me when I am mistaken below.

Q1: which V-by-One standard is supported: original/HS/US?
Clarification: Which of these standards is used for the VBO in Khadas VIM4?

There also seems to be an older V-by-One standard. But I cannot find any specifications for it.

Q2: image bit depth?
Clarification: Can I assume that lcd_bits = 10 together with byte_mode = 4 and color_fmt = 4 refers to the 30bpp RGB /YCbCr444 color mapping in “VBO HS standard 1.52, chapter 4.1 Byte length and Color Mapping”
Screenshot from 2023-03-02 09-18-19
(forum rules prevents me from adding more images of the dts settings)

Q3: framerates supported?
Clarification: VIM4 VBO ouput supports 4k2k@60Hz?

Q4: pixel data order on the 8x VBO lanes?
Clarification: See “VBO HS standard 1.52, chapter 4.2 Multiple Data Lane Combination”. Is region_num = 1, specifying that pixels are transferred like Figure 27? (and not like Figure 28,29?)
(forum rules prevents me from adding image of the dts setting)

Q1: It supports original, bit_rate max 3G.

Q2: 10bits rgb+byte_mode 4 is the standard configuration of the vbyone 4k screen and can be supported. Yuv format is not currently supported.

Q3: supports 4k60hz, and the version of vbyone is v1.4

Q4: region_num can support 1/2/4