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DLPLCR6500EVM: Video Pattern Mode blinks between frames

Part Number: DLPLCR6500EVM

Hello,

I have a problem with the Video Pattern mode. My goal is to play binary patterns at a framerate higher than 120Hz.

For testing purposes, I created a movie, which consists of this stripe pattern

moving in increments of 24 stripes per frame (the darkest red line from the second frame aligns with the brightest blue line of the first frame) at 60 Hz. When I just display this static frame, I get a moving line on the DMD (corresponding to the 24 bit-planes). The setup I used, consists of all 24 bitplanes (r0,r1,...,g0,g1,...,b0,b1,...) shown one after the other : 

settings.txt
Video Mode
8,1,694,0,1,1,1
9,1,694,0,1,0,1
10,1,694,0,1,0,1
11,1,694,0,1,0,1
12,1,694,0,1,0,1
13,1,694,0,1,0,1
14,1,694,0,1,0,1
15,1,694,0,1,0,1
0,1,694,0,2,0,1
1,1,694,0,2,0,1
2,1,694,0,2,0,1
3,1,694,0,2,0,1
4,1,694,0,2,0,1
5,1,694,0,2,0,1
6,1,694,0,2,0,1
7,1,694,0,2,0,1
16,1,694,0,4,0,1
17,1,694,0,4,0,1
18,1,694,0,4,0,1
19,1,694,0,4,0,1
20,1,694,0,4,0,1
21,1,694,0,4,0,1
22,1,694,0,4,0,1
23,1,694,0,4,0,1

As soon as I start playing my movie (the DMD board is set to 60fps and the exposure time is set to 1/(60*24)s = 694us and v-sync is enabled), the moving line starts scanning the whole DMD chip, which is exactly what I intended.

But as I filmed the scanning line at 240fps, there was an obvious discontinuity in the motion between the frames (-> the 24 bitplanes produce a smooth scanning line, but before the 24 bitplanes from the next frame are shown, there is a rather big interval, where the DMD chip displays all 'black' (all zeros))

/cfs-file/__key/communityserver-discussions-components-files/94/SlowMotion240fps.MOV

There seems to be some timing issue, but I can't figure out what I can do besides tweaking the exposure time and turning on v-sync. Maybe there is also a problem with my video player (MPC-HC, playing back lossless RLE frames at 60fps). What would be the best approach to output steady 60fps of a few predefined images over DP or HDMI? In the end, I just want to mimic the Pattern On-The-Fly Mode without the immense loading times (because my patterns are too complex for an effective RLE).

Some help would be greatly appreciated.

Robert

  • Hi Robert,

    DLPLCR6500EVM supports 8 bit video pattern mode upto 240Hz which corresponds to 80Hz 24bit RGB video pattern.

    -ykc
  • Hello ykc,

    thank you for your quick answer. Excuse me for not making my intentions/problems sufficiently clear.
    I want to transmit only 1-bit patterns at high fps (1440 fps e.g.).
    I already partially solved my problem by shaving off a few us from the exposure time, which leaves me at 690us exposure time and a 'black gap' of around 100us between the frames (the DMD displays 24 1-bit patterns at 690us each, leaves a gap of 100u and displays the next 24 1-bit patterns). As soon as I try to further decrease this 100us gap, the DMD skips a frame and leaves me with a huge 1/60s = 16.7ms gap between the frames. My guess would be that the board needs 100us to update to the new frame, which is fine for my application.

    The only thing that still bothers me, is an occasional jump in the gap from 100us to about 200us, accompanied by a 'Sequencer Abort Status Flag Error'. Even at a gap size of 1ms (exposure of 650us per 1-bit plane), the error/jumping occurs every second or so. I think that the error is related to some frequency fluctuation in the video source (DP).

    To summarize:
    Is it right that the 100us gap time is related to the update time and cannot be decreased beyond 100us?
    Is it correct that the gap time jumping (+'Sequencer Abort Status Flag Error') could be attributed to a fluctuating/inconsistent video source?
    How can I avoid getting this 'Sequencer Abort Status Flag Error' so frequently?

    -Robert
  • Hi Robert,

    105us is minimum gap between frames. Can you try this?

    -ykc
  • Hi Robert,

    Were you able to solve the problem?

    -ykc
  • Hi Robert,

    I haven't heard back from you. I assume you were able to fix the problem. I am marking this resolved. In case of any issue then please reply in this thread or create new thread in case this thread is locked.
  • Hello ykc,

    thank you for your reply. The timing from my last post (690us per bitplane, 24 bitplanes, 60fps -> 1440 bitplanes per second) should result in a gap of slightly more than 105us.

    This results in this twitching, combined with a Sequencer Abort Status Flag Error (occurs 3 times in this video):

    The two voltages are the two output triggers (Out 1 on top, Out 2 below). These are the settings I used: 

    7840.settings.txt
    Video Mode
    8,1,690,0,1,1,1
    9,1,690,0,1,0,1
    10,1,690,0,1,0,1
    11,1,690,0,1,0,1
    12,1,690,0,1,0,1
    13,1,690,0,1,0,1
    14,1,690,0,1,0,1
    15,1,690,0,1,0,1
    0,1,690,0,2,0,1
    1,1,690,0,2,0,1
    2,1,690,0,2,0,1
    3,1,690,0,2,0,1
    4,1,690,0,2,0,1
    5,1,690,0,2,0,1
    6,1,690,0,2,0,1
    7,1,690,0,2,0,1
    16,1,690,0,4,0,1
    17,1,690,0,4,0,1
    18,1,690,0,4,0,1
    19,1,690,0,4,0,1
    20,1,690,0,4,0,1
    21,1,690,0,4,0,1
    22,1,690,0,4,0,1
    23,1,690,0,4,0,1
    

    Further lowering the time per bitplane from 690us to 600us or lower does not decrease the frequency of this error/twitching.

    If this twitching only slightly shifts the timing of the bitplanes (as the oscilloscope suggests), it would not pose a big problem for my project. 

    It would only be a problem if one or more frames would be dropped because of this error.

    I was not able to check the completeness of the transmitted frames yet, because of a lack of a better slow motion camera.

    It would be great if someone could try to replicate this behavior to disproof my concern about dropped frames/incompleteness.

    I am using DisplayPort at 60fps in Video Pattern Mode with the settings file from above.

    -Robert

  • Hi Robert,

    I am working on reproducing this. Please expect delay of few days in response.

    -ykc
  • Hi Robert,

    I am unable to reproduce this. I used display port 60hz with your settings file. I don't see sequencer abort error.
    Please check your video source.

    -ykc
  • Hello ykc,

    thank you for your effort. I tried using video signals (DisplayPort) from two different computers at different Hz settings (24,30,60,120) and I always get the sequencer abort error (occurs from every few seconds to constantly being ticked), even when I just display one bitplane per frame.
    I also tried to plug out every other display (only DMD plugged in) with no luck (error still occurs).
    Is it possible, that the problem is related to VSYNC being turned off? I am just using my Windows wallpaper as a test and I am not sure if VSYNC is activated in this case. What was your exact setup when you were trying to reproduce the error? DisplayPort or HDMI? 60Hz? Just the plain Windows wallpaper or something like a special program, which displays your desired frames?

    -Robert

    Edit: I tried using another PC with HDMI at different refresh rates (30 and 60) with no success. 

  • Hi Robert,

    I used hdmi 60Hz. Your settings file worked fine. Are you using TI EVM or your own custom board? Also which version of firmware and GUI are you using?

    -ykc
  • Hello yck,

    I am using the original Texas Instruments DLPLCR6500EVM (bought from Mouser Germany).  My firmware is version 4.1.0 (DLPR900PROM-6500-V4.1.0) and my GUI is version 4.0.1. My board is connected to a stable 12V (1A max) power adapter via a Female Center Positive DC Connector and to my computer via USB and DisplayPort (or HDMI). The only thing I 'modified' is the jumper from the output trigger (to set the proper output trigger voltage level), which I measure with an oscilloscope (the error also occurs, when no oscilloscope is connected to the output trigger).

    -Robert

  • Hi Robert,

    Can you try fw  version 5.0.0 I used version 5.0 .0.

    Thanks,

    Ykc

  • Hello ykc,

    this immediately solved my problem. No more jitter/glitches and no more errors in the GUI.
    Thank you very much for your help.

    -Robert