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How can I define the lcdif_modedb ??

Question asked by 호영 노 on Dec 1, 2017
Latest reply on Dec 4, 2017 by 호영 노

Hi, 

I testing the LCD output but I cannot see a perfect and clear output yet.

 

My First Question was this : ADV7125 with Imx6 is not working normally 

 

I found out DISP0_DAT16~DISP0_DAT23 was not set normally. 

So I can see red color now.

 

But I cannot calculate the correct timing for my resolution.

I wanna set the my frame buffer to 640x480, 60Hz, RGB24, bpp=32.

 

I set the lcdif_modedb like this : 

{
"640x480", // name
   60, // refresh
   640, // xres
   480, // yres

   39721, // pixclock

   16, // left margin (HBP) Back Porch
   48, // right margin (HFP) Front Porch

   2, // upper margin (VBP) Back Porch
   25, // lower margin (VFP) Front Porch

   96, // Hsync Length
   2, // VSync Length

   FB_SYNC_CLK_LAT_FALL, // Sync
   FB_VMODE_NONINTERLACED, // Vmode
0,},

 

 

Actually, I refer from below data. from googling. 

But this make shifted output. 

 

 

 

My upper setting value makes better output. Like this : 

 

This Image is 4 seperated color that (R 255), (G 255), (B 255), (R255G255B255).

 

Red and green, blue and white's boarder line looks like gradation.

 

My original image is this : (640 x 480)

 

At this time, fbset's result is 

mode "640x480-62"
# D: 25.176 MHz, H: 31.469 kHz, V: 61.826 Hz
   geometry 640 480 640 480 32
   timings 39721 16 48 2 25 96 2
   rgba 8/16,8/8,8/0,8/24
endmode

 

PCLK and VSYNC is holded.

but HSYNC looks like jitter. (little bit.. shaking..)

 

I cannot understand..

 

 

So I tried another timing and resolution.

I setted

{
"1280x960", // name
60, // refresh
1280, // xres
960, // yres

9794, // pixclock

216, // left margin (HBP) Back Porch
80, // right margin (HFP) Front Porch

30, // upper margin (VBP) Back Porch
1, // lower margin (VFP) Front Porch

136, // Hsync Length
3, // VSync Length

FB_SYNC_CLK_LAT_FALL, // Sync
FB_VMODE_NONINTERLACED, // Vmode
0,},

 

And result is 

 

 

Image size is 640x480 and resolution is 1280x960

so, I understood height is half.

but I cannot understand why width is not half..

 

Most of all, 

Left and middle's border line looks like blur and gradation..

 

 

How can I found the exact timing for 640 480 resolution? 

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