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DLPC3479: Max exposure time

Uryyy
Expert 1890 points
Part Number: DLPC3479
Other Parts Discussed in Thread: DLPC3470, DLPC3478

Tool/software:

Hello TI,

I'd like to know the maximum exposure time as shown bellow. 

https://e2e.ti.com/support/dlp-products-group/dlp/f/dlp-products-forum/778576/faq-sequence-timings-for-dlpc347x-light-control-platform

Regarding Mono 8bits' sequence 20, maximum exposure time is 7600usec. How the value is caluculated? Can we configure over 7600usec?

Regards,

Uryyy

  • 0
    TI__Genius 11900 points

    Hello Uryyy,

    Thanks for reaching out again through E2E!

    The FAQ you've referenced is used in an Internal Pattern Streaming Mode. I'd recommend you take a look at the Firmware Selector Tool and the specific controller you are looking at.

    That general FAQ does not relate to all DLPC347x controllers or the many versions since this was created. Thank you for pointing this out, this is something that should be cleaned up.

    The value is calculated via our internal solution which utilizes different sequences based on the exposure times - Sequence Database v0.5.70 in FAQ and v0.5.71 in our latest release (DLPC3478/DLPC3470 - note that DLPC3479 has a separate sequence database).

    Best,

    Aaron

  • 0 in reply to Aaron Black
    Expert 1890 points

    Hello Aron,

    I'd like to maximize exposure time within 6.6msec/frame. What should I set the each parameters(Pre-dark time/Exposure time/Post-dark time)?

    Thank you,

    Uryyy

  • 0 in reply to Uryyy
    TI__Genius 11900 points

    Hello Uryyy,

    From everything I've gathered that you are using Internal Pattern Mode on the DLPC3478 controller - please advise if this is not the case as the DLPC3479 cannot run 8-bit mono patterns at ~7.6ms.

    If you are trying to run a frame of 6.6ms the combination of Pre/Post-Exposure Dark Time and Exposure Time should be 6.6ms. You have the ability to adjust these timings in the EVM GUI.

    Best,

    Aaron

  • 0 in reply to Aaron Black
    Expert 1890 points

    Hello Aron,

    As you said, I had refferred incorrect URL of DLPC3478. The DLPC3479(Release Notes) allows max 4168usec. The official answer of TI as time settings is "Dark time(Pre+Post)" should be "6.6msec-4.168msec". Is my understanding correct?

    I'm glad if I can set "6.6msec-171usec(min pre dark time)-31usec(min post dark time)" as exposure time.

    Thank you,

    Uryyy

  • 0 in reply to Uryyy
    TI__Genius 11900 points

    Hello Uryyy,

    Yes, this should be good. Play with timings around this as min timings are noted as almost absolute min timings. I'd recommend give a buffer of ~20% or so.

    Best,

    Aaron 

  • 0 in reply to Aaron Black
    Expert 1890 points

    Hello Aron,

    Sorry for the same question. I'd like to know why you decide max exposure time of the sequense 22 is 4168.

    Regards,

    Uryyy

  • 0 in reply to Uryyy
    TI__Genius 11900 points

    Hello Uryyy,

    As I've said before:

    Aaron Black said:
    The value is calculated via our internal solution which utilizes different sequences based on the exposure times

    This is the total exposure time, which inversely equals the frame rate. 

    The timing table ranges are a characteristic of the DMD and TI Intellectual Property, so I cannot share much about this.

    If this is pure curiosity, I'm sorry I can't be more direct. If you have an issue with this specific exposure time range, please share what the issue is and we'd be happy to address this!

    Best,

    Aaron

  • 0 in reply to Aaron Black
    Expert 1890 points

    Hello Aron,

    Thank you for the explanation again. I understood we can't know the root mechanism of the values. In the first place, why do you define the upper limit of the exposure time?　I feel like that there was not upper limit in old versions.

    Regards,

    Uryyy

  • 0 in reply to Uryyy
    TI__Genius 11900 points

    Hello Uryyy,

    The reason is because the software will automatically change to the next sequence if it is within the next range.

    Honestly, you and other customers don't need to know the sequence number as this doesn't mean anything to you. It is a reference for us internally to know which sequence is being used if there is an issue actually seen.

    Best,

    Aaron