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DLP6500FLQ: DLP6500 Pattern Switching

TI-CSC
Genius 9610 points
Part Number: DLP6500FLQ
Other Parts Discussed in Thread: DLPC900, DLPC410

Hello E2yE Experts, 

Good day.

We currently have an issue with the DLP 6500.  We want to know how fast the patterns can switch, so we did the measurement with a photodiode.  What we found is that, even with a static pattern, the DMD always refreshes itself every 105 us, and we can not find a way to stop it. It's a huge problem for us, most of the time we just want it to project a static pattern for many seconds, do you know how to stop this internal refreshing cycle?  

Thank you in advance.

Regards,

CSC

  • 0
    TI__Intellectual 1410 points

    Hello CSC,

    Thank you for reaching out.

    May I ask which of the pattern modes are you using?

    Also, what are the exposure time, dark time, and bit-depth?

    Thank you,

    With regards,

    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Genius 9610 points

    Hello Aishwarya,

    Good day.

    I'm using Pattern On-The-Fly mode, the exposure time is 2s, with no dark time, I don't know what bit depth is, we just project a box pattern. Also, we use an external trigger. 
    If it's okay, I can send you some pictures and short videos of our measurements using a photodiode.
    The picture attached shows the situation when I project a static pattern for 2s, and the video shows the situation when I externally triggered multiple images in cycles. Both cases have a problem. 
    Regards,
    CSC
  • 0 in reply to TI-CSC
    TI__Intellectual 1410 points

    Hello CSC,

    Thank you for the images. Please give me some time to analyze them.

    Thank you,

    With regards,
    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Intellectual 1410 points

    CSC,

    Are you using the external trigger to advance to next pattern? That would mean you are using the Trigger 1 pin.

    Could you please send scope shots of your trigger pulse with Trigger Out 1 and Trigger Out 2 signals?

    Also, what FW version are you currently using?

    Thank you,

    With regards,
    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Genius 9610 points

    Hello Aishwarya,

    Good day.

    I have questions:

    1. What's the difference between using trigger 1 input and trigger 2 input?  Right now I see our external trigger connector connects J19 pin2&pin3.

    2. The digital controller we are using is DLPC 900, do you know which pin can provide a frame trigger, not a sequence trigger? 

    Regards,

    CSC

  • 0 in reply to TI-CSC
    TI__Intellectual 1410 points

    CSC,

    1. Trigger In 1 indicates the controller to advance to the next pattern. Trigger In 2 starts and stops the sequence. 
      You can find much detailed explanation about triggers in DLPC900 datasheet, Section 7.4.1
    2. Jumper on J19, between pins 2 and 3 points to your trigger input 1 level being set at 1.8 V.
    3. The very first question you asked about the how fast the patterns can switch, it is as you have found out, 105 us. This is the minimum exposure time that you can set for a 1-bit pattern.
    4. The photodiode scopeshot shows that your image is continuously displayed. But at every 105 us, there is a slight dip. This is because of the micromirror clocking pulses, micromirror resets at every 105 us. This cannot be changed.
    5. When you say frame change, is this in Video mode? 

    Thank you,

    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Genius 9610 points

    Hello Aishwarya,

    Good day.

    We do have another DMD, which is DLP 7000, but the controller board is V4395 from VIALUX. It can perform two trigger settings: master mode or slave mode. The slave mode can trigger just once and hold the mirrors stand for seconds. I want to know if our DLP6500 with DLPC900 controller board is able to do the same thing. 

    Regards,

    CSC

  • 0 in reply to TI-CSC
    TI__Intellectual 1410 points

    CSC,

    Please allow me some time to talk to experts about DLPC410-DLP7000 and provide you with a solution.

    Meanwhile, can you use an image of 8 bit-depth and try capturing photodiode output?

    You can set the bit-depth in the GUI.

    Thank you,

    Aishwarya

  • 0 in reply to Aishwarya K Aithal
    TI__Mastermind 43225 points

    Dear CSC

    Was the customer able to try Aishwarya's suggestion?

    The DLPC900 based systems cannot hold an image without periodic resets the way the DLPC410 based systems can since the underlying ASIC has a refresh reset every 105 us, but the DLPC410 does not.

    I am sorry for any confusion on this point.

    Fizix