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DS90C189-Q1: Can you convert the DPI signal to LVDS

meng Ke
Expert 1140 points

Part Number: DS90C189-Q1

Tool/software:

Hi Ti Experts:

The video can not sending out with the DPI video.

Right now I need to convert the DPI Signal to LVDS signal. Here is the hardware design below:


 

and right now i using the Oscilloscope‌ to measure the signal in VOUT0_DATAx. and there have signal in the PIN.
and the SOC_VOUT0_PCLK signal is below:

  • 0
    Expert 1140 points
    and here is the SOC config for DPI signal 
    static     const struct drm_display_mode boe_av069hdt_a80_2dp0_mode = {
    .clock = 76782,
    .hdisplay = 1280,
    .hsync_start = 1280 + 26,
    .hsync_end = 1280 + 26 + 8,
    .htotal = 1322,
    .vdisplay = 720,
    .vsync_start = 720 + 8,
    .vsync_end = 720 + 8 + 2,
    .vtotal = 733,
    .flags = 0,
    };

    static const struct panel_desc boe_av069hdt_a80_2dp0 = {
    .modes = &boe_av069hdt_a80_2dp0_mode,
    .num_modes = 1,
    .bpc = 8,
    .size = {
    .width = 154,
    .height = 85,
    },
    .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
    .bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE | DRM_BUS_FLAG_SYNC_DRIVE_POSEDGE,
    .connector_type = DRM_MODE_CONNECTOR_DPI,
    };


  • 0 in reply to meng Ke
    TI__Mastermind 31310 points

    Hi Meng,

    Firstly, the MODE0 pin should be pulled low for single LVDS out. In the schematic it is pulled high to 1.8V. Please change this to connect MODE0 to ground.

    For the LVDS output, the LVDS lanes require 100 Ohm termination. The termination can either be external, like the differential resistors, or it can be internal termination within the display sink. If the display has internal termination, then the differential resistors should not be populated for those LVDS lanes.

    Please check whether the LVDS clock output is at the same rate as the input clock. Similar to how you probed the input clock, please check the waveform for the LVDSA_CLK to check the pixel clock frequency.

    After you have input video transmitting, is there an output on the LVDS channel waveforms? Please probe this as well to check that there is activity on these channels.

    Best regards,
    Ikram