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DLP4500: How fast is the Vsync signal in pattern sequence mode

Pang Weng Yeong
Prodigy 140 points
Part Number: DLP4500

Dear TI,

May I know how fast is the Vsync signal period can support when I am using RGB parallel interface during pattern sequence mode? Thank you.

  • 0
    TI__Genius 10925 points

    Hi Pang, 

    Welcome to TI E2E Forums! The LCR4500 EVM can support upto 120Hz Vsync rate in External Pattern Sequence Mode.

  • 0 in reply to Hirak Biswas
    Prodigy 140 points

    Dear Hirak,

    Thanks for your reply.

    So in 120Hz Vsync rate, it supports up to 24bit of data. And the total number of patterns multiplied with the pattern exposure time in this 24bit data must equal or less than 120Hz Vsync rate. Is this right?

    And the pattern exposure time required in different pattern bit have to follow the table highlighted in red below? This table is shown in the DLP4500 light crafter user guide (DLPU011F–July 2013–Revised July 2017).

  • 0 in reply to Hirak Biswas
    Prodigy 140 points

    Dear Hirak,

    Thanks for your reply. After I read the DLP4500 evaluation module user's guide document (DLPU011F–July 2013–Revised July 2017), there are some parts that I am not so clear on the pattern sequence mode.

    1. So in 120Hz Vsync rate, it supports 24bit data. And the total number of patterns multiplied by the pattern exposure time in this 24bit data must equal or less than 120Hz Vsync rate. Is this right?

    2. Besides, does the pattern exposure time required have to follow the external RGB input pattern rate in table 4-1 at page 45 that state in the DLP4500 evaluation module user's guide document (DLPU011F–July 2013–Revised July 2017)?

    3. May I know the Vsync signal can be used for trigger my controller board to transfer the second frame of 24bit data to the light crafter?

    4. When using pattern sequence mode with pattern source from flash, it need load buffer time (~200ms). Does this load buffer time is needed in pattern source from video port?

    Thank you.

  • 0 in reply to Pang Weng Yeong
    TI__Genius 10925 points

    Hi Pang,

    1. You are right. Also kindly note that there are minimum exposure time limits for patterns depending on bitdepths. For example, a 8bit pattern can be displayed for a minimum of 8333us and not less than that.

    2. Yes this table is to be strictly followed.

    3. The external frontend will have to generate the VSYNC signal along with the video pixel data being fed to the EVM. The EVM will use this VSYNC signal to trigger patterns internally.

    4. This load time is only required when displaying pattern sequence from internal splash images when number of images >2. This load time is not required in case of pattern display from external video source.

  • 0 in reply to Hirak Biswas
    Prodigy 140 points

    Dear Hirak,

    3. The external frontend will have to generate the VSYNC signal along with the video pixel data being fed to the EVM. The EVM will use this VSYNC signal to trigger patterns internally.

    So I generate Vsync signal to the EVM and at the same time I sending the video pixel data to EVM? In this way, it will not cause EVM projection error issue? As while sending the video pixel data, Vsync signal is send to EVM to trigger patterns internally.

    If I not using pattern sequence mode, I use video mode. The video mode able to supports the frame rate greater than 120Hz or same as 120Hz also?

    What does the pixel data format RGB444 in video mode means?

    Thank you.

  • 0 in reply to Pang Weng Yeong
    TI__Expert 3360 points

    Hello Pang,

    We will get back to you soon with more information.

    Thank you,

    Chris

  • 0 in reply to Cody Smith
    Prodigy 140 points

    Dear Chris,

    Any update for the followings things.

    1. How Vsync signal is sent to the EVM and synchronize with EVM projection?

    2. what is the frame rate for video mode?

    Thank you.

    Best regrads,

    Pang Weng Yeong 

  • 0 in reply to Pang Weng Yeong
    TI__Genius 10925 points

    Hi Pang, 

    1. The VSYNC signal is sent along with the video data in parallel port. If you are using the LCR4500 HDMI mode then your frontend will send the vsync,hsync etc over HDMI along with the video input data. 
    2. The input framerate supported in pattern sequence from video mode is upto 120Hz, and in video mode (not pattern sequence) the input framerate supported is upto 60 Hz.

  • 0 in reply to Hirak Biswas
    Prodigy 140 points

    Dear Hirak,

    Noted. Thanks a lot. =)