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1000 fps binary display

Yun-Ho Jang
Prodigy 65 points
Other Parts Discussed in Thread: DLPC200

Hi, 

I'm new here and trying to obtain 1000 fps binary display with dlpc200. I need to synchronize each binary pattern to the corresponding sample position. 

After I went through various threads here, I may have two option to obtain my goal. One is to download all binary patterns to the memory and execute it by calling LUT. This is the only way to achieve the highest frame rate and pattern sync, but we need to download every 1000 images whenever the image sets should be changed. Every single binary pattern will be different and I may have to download after 1000 patterns are displayed. I read some answers that the download is not fast compared to the frame rate. Is this correct? 

The second method would be the structure light mode via DVI with packing 20 bits to one frame and running the dmd with 50 fps. I think I should go this method, but I wonder the each bit plane (among 1000 bit planes) has same on time like 1 ms? The binary weighting is not applied to the structure light mode? I also want to know if there is a way to sync each bit plane in this mode. 

Thank you. 

Yun-Ho

  • 0
    TI__Mastermind 30875 points

    Hello Yun-Ho,

    The second method would be the structure light mode via DVI with packing 20 bits to one frame and running the dmd with 50 fps. I think I should go this method, but I wonder the each bit plane (among 1000 bit planes) has same on time like 1 ms? The binary weighting is not applied to the structure light mode? I also want to know if there is a way to sync each bit plane in this mode. 

    Yes, each bit-plane as same ON time of 1ms. For 1bpp patterns the binary weighting is same for all, not sure I understood your question. For the sync, actually you will get the periodic sync at the 3 output sync port. So for 50Hz source input you will see 20 output triggers which 1 trigger per binary pattern.

    Regards,

    Sanjeev


  • 0 in reply to Sanjeev
    Prodigy 65 points

    Hello Sanjeev, 

    Thank you for your reply. Regarding the sync, you mean I'll get 1000 triggers per second if I send 20 bit 50 fps patterns? 

    I also want to know how long it will take if I download 1000 binary patterns to external memory. I'd like to compare which way (DVI port vs. External memory) will be better for my application. 

    Thank you again.

    Best regards, 

    Yun-Ho

  • 0 in reply to Yun-Ho Jang
    TI__Mastermind 30875 points

    Hello Yun-Ho,

    Yes, you will get 1000 triggers per second. About sending the data, note that the DLPC200 accepts data at the HDMI port as 24bit (RGB888) so when you have configured patterns/frame = 20, the remaining 4 patterns are not displayed even though you are sending 24bit frame. About the packing it is discussed in this thread http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/387/t/271050.aspx

    About the direct download patterns using USB,  it is too low, if i remember correctly it is < 10 patterns/seconds. So it is not possible to achieve the 1000 binary patterns speed.

    Regards,

    Sanjeev

  • 0 in reply to Sanjeev
    Prodigy 65 points

    Thank you for your reply. It is very helpful to understand the communication with DLPC200.

    I have one more question regarding this topic. You said when I configure 20 patterns/frame, the remaining 4 patterns will not be displayed. Does it mean that 4 patterns still affect the effective pattern rate? In other words, I'd like to display 1000 binary patterns per second (20 patterns per frame x 50 frame per second) and each pattern should be displayed for only 1 ms. However the DLPC200 always accept data in the form of 24 bit, so I need to pack the data with extra 4 bits of all zeros. Does these blank 4 bits affect the pattern exposure time? Or they'll be ignored and the next 20 bits will be displayed after the first 20 bits. 

    Best regards, 

    Yun-Ho

  • 0 in reply to Yun-Ho Jang
    TI__Mastermind 30875 points

    Hi Yun-Ho,

    RGB 24bit is a standard video timing format. The extra 4 bits would never is used in displaying. As you know we are configuring the DLPC200 to effectively display 20patterns/frame. Since they are not referred while displaying this will not impact the pattern exposure time. The available 50Hz or 20ms time is utilized to display 20 1bpp patterns so there is no question of loosing the exposure time.

    Regards,

    Sanjeev