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DLP4710EVM-LC: Low framerate external pattern mode through HDMI

Gabriel Seigneur
Prodigy 20 points
Part Number: DLP4710EVM-LC
Other Parts Discussed in Thread: DLP4710, DLPC3479

Tool/software:

Hi,

I want to use my DLP4710 Light Control chipset in external pattern mode, to display 1-bit patterns with an exposure time of at least 1 second (maybe 2 or more - the dark time can be as long as the DMD needs).

I have two questions on this:

1) My understanding is that the only way to send my frames to the DLPC3479 controller's is to use the HDMI port. I cannot directly flash my patterns through SPI and have the controller read them from the flash memory, can I?

2) The IT6801 HDMI receiver only accepts certain framerates in 1080p, all way too high for my use. Can still use this with the whole Light Control chipset to display patterns at a framerate below 1 Hz? (I might need 0.1 Hz or something in the end, but that's a great order of magnitude). I'm thinking of using an FPGA to send in my patterns over HDMI. Can you confirm that's possible idea?

3) If I can't have the HDMI work at such a framerate, can I "teach" the controller to "skip" frames and therefore display patterns at a lower framerate than that of the HDMI input? So far, I tried this with the GUI, purposedly having a mismatch of framerates between the HDMI input and that in the external pattern mode settings. it did not work.

Is there a firmware where I can use Trigger IN to display only the latest frame (at a pre-specificed timing)?

Thanks a lot.

Best,

Gabriel

  • 0
    TI__Expert 3625 points

    Hello Gabriel,

    Thank you for reaching out to us. I have assigned the thread to an expert. Please expect a delay in response due to the holidays.

    Thank you for your patience and wish you a very happy new year!

    Regards,
    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Genius 11860 points

    Hello Gabriel!

    Thanks for reaching out through E2E!

    1. While running in External Pattern mode the patterns need to be sent to the controller over parallel interface - typically converted from HDMI, yes.

    2. Could you advise why you would like to run patterns at such a slow rate? As mentioned is Q2, the front-end module utilizes parallel input and as long as you have a front-end solution system that produces the correct reference. Longer exposure times than those that are mentioned in the latest software release notes will operate with decreased timing accuracy, but usually we operate near the 200ns to ~22ms exposure times.

    3. I suppose you could set the pre or post dark time to extended periods of time and that would be close to the same as 'skipping' frames?

    4. The Trigger In of the DLPC3479 is not active in External Pattern Display but in Internal Pattern mode it advances the the next pattern. I would recommend you look into Internal Pattern mode, I can't understand your application as well as you can.

    Best,

    Aaron