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DLPC300 OUTPUT_TRIGGER signal pulse width

Rossinag
Expert 1705 points
Other Parts Discussed in Thread: DLPC300

Dear All,

Please let me ask you about the DLPC300 OUTPUT_TRIGGER signal pulse width when it is ebnabled.

It looks like there is not the pulse width spec in the dlpc300 data sheet.

Is it possible to share the spec?

Thank you and best regards,

Rossinag. 

  • 0
    TI__Expert 4500 points

    Dear Rossinag,

    The maximum Output trigger pulse width is 2 seconds.

    Regards,

    Divya

  • 0 in reply to Divya Reddy
    Expert 1705 points

    Dear Divya,

    Thank you for your reply. Please let me ask you more detail.

    Is the OUTPUT_TRIGGER pulse width variable?

    I would like to know the pulse width of 8-bit Monochrome External Video case.

    Thank you and best regards,

    Rossinag

  • 0 in reply to Rossinag
    Prodigy 80 points

    As far as I can tell, the pulse width can always be set over the USB commands, regardless of the video mode being used (in particular, I was using the 1 bit monochrome over HDMI). In the GUI, the "Output Trigger Setting" section on the bottom left of the "Pattern Sequence" tab lets you set the pulse width, and applies to the HDMI video as well as the pattern sequence mode.

  • 0 in reply to Logan Clark
    Expert 1705 points

    Thank you very much for your input. I understood the the trigger setting of the LightCrafter eveluation module.

    But it looks like it does not influence DLPC300's OUTPUT_TRIGGER signal configuration. 

    We are in designing phase of original control board without using the DM365,optional FPGA, therefore we are investigating the DLPC300's OUTPUT_TRIGGER signal spec.  Hopefully, I would like to know its information.

    Thank you and best regards,

    Rossinag

  • 0 in reply to Rossinag
    TI__Expert 4500 points

    Hi Rossinag,

    I believe the DLPC300 OUTPUT_TRIGGER can be used without the FPGA and DM365. In the current design, this signal (TSTPT_6 on DLPC300) is input to the FPGA (DLP_OUT_TSTPT6) and the FPGA generates the output triggers.

    I will have to check the specifications and see how you can enable this signal in External video mode. I will provide you a response on Monday.

    Regards,

    Divya

  • 0 in reply to Divya Reddy
    TI__Mastermind 30875 points

    Hello Rossinag,

    I will answer to your question on behalf of Divya.

    Irrespective of display mode, the DLPC300 O/P trigger pulse is fixed without FPGA. The fixed pulse width is 5uSec. 

    Regards,

    Sanjeev

  • 0 in reply to Sanjeev
    Expert 1705 points

    Hello Sanjeev, Divya.

    Thank you for your reply. I understand.

    Best regards,

    Rossinag

  • 0 in reply to Rossinag
    TI__Mastermind 30875 points

    Dear Rossinag,

    There is a mistake in my response about the trigger pulse width information. I apologize for the mistake from my side. Please hold on for correct response. I will soon be updating the this thread.

    Regards,

    Sanjeev

  • 0 in reply to Sanjeev
    TI__Mastermind 30875 points

    Hello Rossinag,

    As I mentioned earlier the output trigger pulse is fixed when it it used without FPGA and DM365.

    The pulse width can be determined using below formula.

    Monochrome External Video Case:

    For bit-depths between 1 through 7  OutputTrigger pulse width (in uSec) = ( 1/frame_rate ) * (1 / (floor)(24/pattern_bit_depth) ) * 10^6

    For bit-depth 8                                          OutputTrigger pulse width (in uSec) = ( 1/frame_rate ) * (1 /  ( (24/8) -1) ) * 10^6 

    Example:

    1bpp patterns at 60Hz in the Monochrome External video case will be (1/60) * (1/ (24/1)) * 10^6 = 694.44uSec the actual measured value on the photo detector would be close to ~670uSec this is because in the formula above we have not considered other overhead timings it will be between 2 to 3% of the actual value.

    Similarly applying the same math for 2bpp patterns @ 60Hz from the formula it will be 1388uSec again the actual measure value will be 1349uSec

    In case of 8bpp @ 60Hz the pulse width according to formula it is 8333uSec actual measured value will be around 8148.45uSec

    You can use the above formula to approximately find the output trigger pulse width value for other bit depth patterns.

    Let me know if anything not clear.

    Regards,

    Sanjeev

  • 0 in reply to Sanjeev
    Expert 1705 points

    Hello Sanjeev,

    Thank you for the correction.

    I understand that the dlpc300's "OUTPUT_TRIGGER" signal will be asserting while a pattern image exists on the DMD.

    So , in the 8 bit monochrome case, the 8 bit planes will be displaying while the "OUTPUT_TRIGGER" is asserted.

    If I am misunderstanding please let me know.

     

    Thank you and best regards,

    Rossinag

  • 0 in reply to Rossinag
    TI__Mastermind 30875 points

    Hello Rossinag,

    Your understanding is correct.

    Regards,

    Sanjeev