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SN65DSI86EVM: Request for further detail on section 3 Quick Start of the user manual

Part Number: SN65DSI86EVM
Other Parts Discussed in Thread: SN65DSI86, TEST2

Hi,

     The user manual for the SN65DSI86EVM version June 2014 provides a section titled quick start and it shows a picture of what appears to be a processor board connected to the EVM. However the document doesn't contain any further information on this board. Would it possible for you to provide further details on this setup? Particularly around which board this is and whether this could be used as a tested reference implementation. We are currently trying to debug an issue with the design of one of our products and it would be useful to have details of this reference platform in order to assist with our development.

Many thanks

Ben Taylor

  • Ben

    This is the Pandaboard OMAP EVM we used to validate the DSI86.

    But you can use other DSI source to test out the DSI86. What is the specific issue you have with the DSI86?

    Thanks

    David

  • Hi David,

                   Many thanks for your response. Currently we are having issues integrating our imx8mm based processor board running Linux with the SN65DSI86. We are uncertain whether these issues are software related or hardware. So we were looking to obtain a known working hardware reference platform, so we could then narrow down the source of the issue hence the original question. Is there also any chance you could give any more details on the software build of the test system you used. Was it for example running Linux and if so which version? The issues we are currently looking at are described in the post at:

    Presumably in your test setup you didn't experience any issues similar to this?

    Regards

    Ben

  • Ben

    The code was written specifically for the OMAP 460 EVM.

    I wrote a DSI86 debugging guide on the e2e forum and we can use this guide to debug your issue: 

    Is this an eDP or DP application and are you able to get the color bar to work in your design?

    Thanks
    David   

  • Hi David,

                   Many thanks for your continued support. I can confirm we are developing a DP application for our product. I have read this on the datasheet of the device.

    Because it does not support HDCP, it is only intended for internal applications like notebooks and tablets.

    This suggests the chip is only suitable for eDP applications and does not provide a fully compatible DP interface. Are there any other limitations to the device that may mean that we are likely to encounter issues when using monitors that have implemented the DP protocol? I've heard that all new monitors require an implementation of HDCP, do you know if this is the case? Or there are any other issues that are likely to prevent the interoperability between the bridge and DP monitors currently on the market?

    Regards

    Ben

  • Ben

    Most DP monitors do not support ASSR. I would recommend you go ahead and disable ASSR in the DSI86.

    To disable ASSR, make sure TEST2 pin is be sampled high at the rising edge of EN pin. It is recommended to pull TEST2 pin to 1.8V thru a 1k to 10k resistor. Once TEST2 is high, the following steps must be performed:


    1. Write 0x07 to register 0xFF. This will select Page 7.
    2. Write 0x01 to register 0x16. This will make ASSR_CONTROL to be read/write.
    3. Write 0x00 to register 0xFF. This will select Page 0.
    4. Write 0 to bits 1:0 at register 0x5A. This will change from ASSR to Standard DP.

    Once the ASSR is disabled and you are still seeing the issue, I would suggest we enable the color bar and see if the color bar works or not.

    Thanks

    David

  • Hi David,

                   We have been testing with the above settings and it appears to make a difference to compatibility. Does this have the potential to impact any other aspects of the device (e.g. radiated emissions), or can we leave TEST2 permanently pulled high?

    Regards

    Ben

  • Ben

    I do not see an issue leaving the TEST2 pin high, the TEST2 pin must be high to disable the DSI86 ASSR.

    Thanks
    David