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4DPi-35-II and HDMI at the same time

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  • 4DPi-35-II and HDMI at the same time

    I am trying to use the 4DPi-35-II as a secondary display. I want to boot to the HDMI and do basically everything from the HDMI, but I want a readout to be displayed on the 4DPi-35-II using the framebuffer device.

    I could do this using a display I purchased off eBay. I could just use a device tree overlay and everything was ready to go. It seems these displays are much more complicated having custom kernels.

    Is there any way to do what I want with these displays?

  • #2
    Hi Glenn,

    Welcome to the forum,

    With the custom kernel that we have for 4DPi-32-II, it does not support to be use simultaneously with HDMI. Instead I can suggest trying some of our HMI products as secondary display which you can communicate using UART.

    Thank you.

    Best Regards,
    Ferdinand

    Comment


    • #3
      Originally posted by frsantiago View Post
      Hi Glenn,

      Welcome to the forum,

      With the custom kernel that we have for 4DPi-32-II, it does not support to be use simultaneously with HDMI. Instead I can suggest trying some of our HMI products as secondary display which you can communicate using UART.

      Thank you.

      Best Regards,
      Ferdinand
      wow!
      So if I use one of your SPI displays 4DPI-*, then I'm going to loose HDMI output completely ? :-O

      Comment


      • #4
        Good day!

        Originally posted by SFR75 View Post
        wow!
        So if I use one of your SPI displays 4DPI-*, then I'm going to loose HDMI output completely ? :-O
        As mentioned by Ferdinand previously, you can't use both the HDMI and 4DPi as output at the same time.

        This doesn't mean that you can't swap between them. Here's a short discussion from the datasheet regarding this:

        Click image for larger version

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        I hope this helps.

        Best Regards
        Juniel Cruz

        Comment


        • #5
          Originally posted by Juniel Cruz View Post
          Good day!



          As mentioned by Ferdinand previously, you can't use both the HDMI and 4DPi as output at the same time.

          This doesn't mean that you can't swap between them. Here's a short discussion from the datasheet regarding this:

          Click image for larger version  Name:	TFTnHDMI.jpg Views:	2 Size:	41.0 KB ID:	74791

          I hope this helps.

          Best Regards
          That's a quite sever limitation, if you ask me.
          I think the idea of having an extra mini-screen is to provide UI/diagnostics on what happends in raspberry, when operating in stand-alone mode.
          So for any graphics application this won't work....

          Comment


          • #6
            Hello,

            Originally posted by SFR75 View Post
            That's a quite sever limitation, if you ask me. I think the idea of having an extra mini-screen is to provide UI/diagnostics on what happends in raspberry, when operating in stand-alone mode.
            The 4DPi screen is intended to be used as the main screen or what we refer to as Primary Displays. This essentially removes the need for an HDMI monitor. However, a lot of Raspberry Pi applications are headless, simply not using HDMI. In these applications, primary displays can still be used for diagnostics.

            If your main goal is to use an additional screen for diagnostics, you should also be looking into Secondary Displays. This type of display adds additional UI capabilities to Raspberry Pi and doesn't involve redirecting the HDMI output to the display.

            For a brief information regarding this, please see this article: What is the difference between primary and secondary display solutions for Raspberry Pi?

            Originally posted by SFR75 View Post
            I think the idea of having an extra mini-screen is to provide UI/diagnostics on what happends in raspberry, when operating in stand-alone mode.
            So for any graphics application this won't work....
            That not exactly true. Not everyone will need a diagnostics screen separate from HDMI output.

            Most of the time, a touch screen display will be used as a human-machine interface which allows users to control the Raspberry Pi's behavior. Applications such as this usually removes the desktop environment to reduce system usage and boots directly to their application.

            Also, as far as system diagnostic goes, there are several ways to do this including web hosted diagnostics or via a LAN or WLAN connection.

            Thanks for your understanding.

            Best Regards
            Juniel Cruz

            Comment


            • #7
              Originally posted by Juniel Cruz View Post
              Hello,



              The 4DPi screen is intended to be used as the main screen or what we refer to as Primary Displays. This essentially removes the need for an HDMI monitor. However, a lot of Raspberry Pi applications are headless, simply not using HDMI. In these applications, primary displays can still be used for diagnostics.

              If your main goal is to use an additional screen for diagnostics, you should also be looking into Secondary Displays. This type of display adds additional UI capabilities to Raspberry Pi and doesn't involve redirecting the HDMI output to the display.

              For a brief information regarding this, please see this article: What is the difference between primary and secondary display solutions for Raspberry Pi?



              That not exactly true. Not everyone will need a diagnostics screen separate from HDMI output.

              Most of the time, a touch screen display will be used as a human-machine interface which allows users to control the Raspberry Pi's behavior. Applications such as this usually removes the desktop environment to reduce system usage and boots directly to their application.

              Also, as far as system diagnostic goes, there are several ways to do this including web hosted diagnostics or via a LAN or WLAN connection.

              Thanks for your understanding.

              Best Regards
              In a way you are right when you say that this is a "Primary Display". However it doesn't work exactly as Primary display one would've expected, due to SPI interface.

              Originally I've bought it to build a small video player based on RPI. However after spending many hours I still couldn't achieve descent frame rate. Even with overclocking and kernel OS optimization.

              Then years later (now) I'm building a standalone video-projector subsystem and I thought I could use this display to display various sensors information and provide UI...only to discover that once again it's not possible either, because it's so to speak "Primary Display".

              It's somewhat frustrating...

              M

              ps worth mentioning, that I've purchased almost a hundered of your OLED160 and uLCD-24 couple years ago for a different project and those are great.

              Comment


              • #8
                Good day!

                Originally posted by SFR75 View Post
                In a way you are right when you say that this is a "Primary Display". However it doesn't work exactly as Primary display one would've expected, due to SPI interface.
                We do appreciate your opinion on this matter. However, it would also be best to consider that not all individuals will think this way.

                It wouldn't be fair to say that it doesn't work exactly as a Primary display simply because it is utilizing the SPI interface. As far as I am aware of, there's no general definition involving Primary Displays that would lead anyone to believe it should not be using SPI. If there is any, please bring it to our attention so we can evaluate if we need to use a more proper term instead of "Primary Display".

                Currently, enough resources are provided to users and interested people.to avoid misunderstanding about our products. Pre-sales support is also provided to interested customers who wants clarification and/or confirmation.

                Originally posted by SFR75 View Post
                Originally I've bought it to build a small video player based on RPI. However after spending many hours I still couldn't achieve descent frame rate. Even with overclocking and kernel OS optimization.

                Then years later (now) I'm building a standalone video-projector subsystem and I thought I could use this display to display various sensors information and provide UI...only to discover that once again it's not possible either, because it's so to speak "Primary Display".

                It's somewhat frustrating...
                I understand your frustration. However, please understand that the intended purpose of this display is not to simply display values or play videos but instead to be a human-machine interface which is able to display sensor values, provided user controls etc. The development of this product is not focused on dual output (with HDMI) and playing videos mainly because majority of customers and their needs doesn't fall in this area.

                Furthermore, as you might have realized already. All details/features of our products are provided in the documents which you can find in each of the product pages which could prevent any misunderstanding. If there's anything else you are looking for and is not there, you can always send us your inquiry.

                Lastly, we said, it is not possible but that might not be exactly true. Based on your messages, you have experience in performing kernel level operations. If you are interested, the link to the source files for the kernel package is also available in the downloads section of 4DPi products. You can try and modify this as required and build your own package.

                Originally posted by SFR75 View Post
                ps worth mentioning, that I've purchased almost a hundered of your OLED160 and uLCD-24 couple years ago for a different project and those are great.
                Thanks for using our products in some of your projects. It would be great to see them in action. Feel free to showcase them here in a new forum post if you haven't already.

                Thanks for you kind understanding.

                Juniel Cruz

                Comment

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