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OMAP DSS

learnom learnomg1
Prodigy 80 points


Hi,

I want to configure a vga chip, using omap DSS. Here's the setup.

Datalines: 24, RGB mode.

   .x_res       = 640,
    .y_res       = 480,
    .pixel_clock = 25174,
    .hfp         = 13,
    .hsw         = 96,
    .hbp         = 51,
    .vfp         = 11,
    .vsw         = 2,
    .vbp         = 32,
};


    dssdev->panel.config = OMAP_DSS_LCD_TFT;
    dssdev->panel.timings = ch7025_panel_timings;
    dssdev->panel.recommended_bpp = 24;
    dssdev->panel.acb = 0;
    dssdev->panel.acbi = 0;

    dssdev->phy.dpi.data_lines = 24;
Issue: After board boot up, i get the pixel clock 25.15 which is correct.

I am not running any video samples, but still i see clock pulses on DSS_ACBIAS, and on all the 24 datalines.

1.Can anyone please tell me why there is clock pulses even though iam not sending any data.

2. DSS_ACBIAS can be set up in active matrix mode, in which it will be high only when data is valid. Can anyone tell me how to setup DSS_ACBIAS into that mode.Currently, Iam getting some pulses(35khz) which is not expected.

Thanks in Advance.

  • 0
    Intellectual 695 points

    Since I am assuming you are talking about a parallel interface, after it has been enabled, it should be always sending data. What exactly do you mean by you are not sending any data? Even if you don't have a pipeline enabled, the manager should be sending the default color through the parallel interface at the pixel clock rate set.