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SN65DSI84: I'm trying to connect a 20.3" LCD (3840 x 720) using SN65DSI84. At this time, can the DSI mipi run 20.3" LCD (3840 x 720) with 4lane 1ea in CM4?

huh myoung koo
Prodigy 20 points
Part Number: SN65DSI84
Other Parts Discussed in Thread: SN65DSI85

Tool/software:

hellow

I have an inquiry.
I'm trying to connect a 20.3" dual LVDS LCD (3840 x 720) using SN65DSI84. By the way, I'm trying to use 4lane 1ea for DSI-mipi with SN65DSI84 as shown below. Can I run a 20.3" dual LVDS LCD (3840 x 720)?

Below is the 20.3" dual LVDS LCD Datasheet.

1261.C203RAT01.0_Ver1.0_20200721_202410311751.pdf

  • 0
    TI__Mastermind 22880 points

    Hi,

    This previous FAQ has some information for the DSI to LVDS devices' resolution: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/945185/faq-sn65dsi84-sn65dsi83-sn65dsi84-and-sn65dsi85-resolution-guide

    From the display datasheet you shared, assuming 24 bpp 

    LVDS_CLK = (Htotal * Vtotal * frame_rate) / 2   
                       =  (4000 * 741 * 60 )/2   
                       =    (177.84 MHz) /2
                       = 88.92 MHz, which is within the 25 to 154 MHz LVDS clock range

    Using SN65DSI84, with 4 DSI data lanes

    DSI_CLK = (2 * LVDS_CLK * bpp)/(2 * number_of_DSI_lanes)
                    = (2 * 88.82 MHz * 24)/(2 * 4)
                    = 533.520 MHz, which is not within the 500 MHz DSI clock limit for the SN65DSI84




    However, using the SN65DSI85 with 8 data lanes,

    DSI_CLK = (2 * LVDS_CLK * bpp)/(2 * number_of_DSI_lanes)
                    = (2 * 88.82 MHz * 24)/(2 * 8)
                    = 266.76 MHz, which is not within the 500 MHz limit for the SN65DSI85



    Please consider using the SN65DSI85 instead with 8 MIPI DSI data lanes.


    Best regards,
    Ikram

  • 0 in reply to Ikram Haque
    Prodigy 20 points

    Thank you for your answer, Ikram

    Our solution does not run videos through 20.3" LCD, but only weather or fine dust is updated once at a certain time on the picture screen, so it doesn't matter if the bpp is 18 bits.


    If I use 18 bits of bpp, can I connect the dual LVDS's 20.3" LCD in the form I inquired about?

    Best regards

  • 0 in reply to huh myoung koo
    TI__Mastermind 22880 points

    Hello,

    For the bandwidth I assumed 24 bpp, so 18 bpp also be within the ranges I mentioned. The datasheet mentions that both 18 bpp and 24 bpp are supported.

    Please check that I recommended using the DSI85 part due to the video bandwidth required.

    Best regards,
    Ikram