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Linux/DLPNIRSCANEVM: What is the relationship between pattern and trig_out

Fred Zheng
Prodigy 90 points
Part Number: DLPNIRSCANEVM
Other Parts Discussed in Thread: AM3358, DLPC350

Tool/software: Linux

Hi everyone,

I'm using the NIRscan platform. I have stored 40 24-bit bmp images in the AM3358, and streamed to the DLPC350.

What's the out pattern number of this command: dlp_nirscan -l40 -E250 -S960, and what's the pulse number of trig_out1 and trig_out2?

I measured that the trig_out1 pulse number is 506 and trig_out2 number is 12650. How to calculate this?

What is the relationship between pattern and trig_out?

How can I obtain one trig_out pulse corresponding with one pattern in this mode? Where can I modify the source code?

Thank u! All!

  • 0
    TI__Mastermind 30600 points
    Hi Fred,

    I'm looking into some of the details of your questions, but I'd like to take a stab at address the last question. You're looking to get one trigger output pulse per displayed pattern? All the trigger modes of the DLPC350 should give you this behavior. I recommend that you consult section 8.4 (page 31) of the datasheet: www.ti.com/.../dlps029d.pdf

    What issues are you seeing that you are trying to solve?

    -Paul
  • 0 in reply to Paul Goedeke
    TI__Mastermind 30600 points
    Could you also clarify your question a bit? What does "what's the out pattern number" mean? Are you wondering how many output patterns you'll get with that command?

    -Paul
  • 0 in reply to Paul Goedeke
    Prodigy 90 points
    Hi Paul,

    Thank you!
    Yes, I want to l know how many output patterns I'll get with that command through the RGB interface. That command means loading 40 images and streaming out 960 patterns? Right? But the measured results are not!


    Thank you!
    Fred
  • 0 in reply to Fred Zheng
    TI__Mastermind 30600 points
    Fred,

    To confirm, with your command line you are loading 40 patterns at an exposure of 250us and sampling all 960 bit planes. I would expect that you would see trig_one as 40, because there are 40 patterns and trig_two should have 1 or 2. One concern I have is that your exposure is very short. It should be more than 635us, as described in the user's guide.

    Are you sampling the triggers correctly? Please confirm using the user's guide that you are looking at the right signals.

    Please also confirm that you are using the latest version of the SW. I would also recommend that you attempt to get your desired sequence/scan configuration working on the TI GUI to confirm that your parameters are correct.

    I'll try it on our NIRscan in the next couple business days and let you know if I have the same results.

    -Paul
  • 0 in reply to Paul Goedeke
    Prodigy 90 points

    Hi Paul,

    Did you ever tried on your platform?

    I tried the command dlp_nirscan -l40 -E650 -S960, the trig_out can not stop.

    All I want to do is to stream out certain number of images and sync out with other devices without samples, and the number of images is large. How can I do it with the command.

    And 1 image contains 24 patterns, when exposure time X 24 is less than 17700, one image is displayed once?  right？

     

    Thank you!

    Fred

  • 0 in reply to Fred Zheng
    TI__Mastermind 30600 points
    Hi Fred,

    To use -l40, which loads images, the pattern BMP files have to be named a specific way. They need to be named scan_img_xxx.bmp, where xxx is a 3 digit number starting at 000. In your case you would have scan_img_000.bmp to scan_img_039.bmp.

    The maximum number of BMP files that can be loaded is 46.

    Check the resolution of the BMP files. They should be 912 x 1140.

    You need to change the order of your command to -l40 -S960 -E650

    Can you confirm these things and then try again, seeing if you get the results you're looking for? We generally use the Windows GUI for our work here, so I'm still looking for a way to test the system as you're using it. For now though, let's see if these suggestions fix your issues.

    -Paul