TFT LCD Drive with DE Mode

aneesh.kn · February 1, 2018, 6:34am

Hi,
We are using Colibri vf61 with Linux 2.6
We are trying to drive a densitron display
Display doesnot has Hsync and VSync It has only DE(Data Enable)
How to adjust timing tn panel-simple. c to facilitate the same
Regards

jaski.tx · February 1, 2018, 7:40am

hi aneesh

Could you give some more information about your hardware and software:
Which Hardware version of VF61 are you using? Which carrier board are you using?
Which bsp version? You can fill this in Environment.

Additionally:
Which densitron display exactly do you want to connect? Which connector will u use?

Thanks and best regards
Jaski

aneesh.kn · February 1, 2018, 8:23am

Hardware Version 1.2A
Custom Carrier board developed internally
Version Linux Version 2.6
Attached Datasheet of Display
link text

aneesh.kn · February 1, 2018, 12:28pm

40 pin frc connector is used

jaski.tx · February 1, 2018, 8:59am

Hi aneesh,
please fill the hardware details in Hardware Environment of question. Which connector are you using to connect to your display?

jaski.tx · February 1, 2018, 6:17pm

HI aneesh

Check this site for adjust timings for you application. The sum of hactive = , hback-porch = and hsync-len = , should be 1056 in your case. The sum of vactive = , vback-porch = and vsync-len = , should be 45.
Further you can refer to this picture.

aneesh.kn · February 2, 2018, 6:32am

Data sheet specifies only DataEnable Timings Only. Since it doesnt support HSync and VSync
What configurations should be changed in toradex , so that we can Switch from Sync(Hs,VS) to DataEnable(DE) Mode

jaski.tx · February 2, 2018, 7:49am

DataEnable signal is defined by Front-, back porch and hsync and vsync. The signals for hsync and vsync will be available at the output of module, but you don’t have to use them. Check the timing diagram on page 15. DataEnable is on when hsync or vsync are active.

this settings defines, if the signal is low (0) or high (1) active. This you have to try with the given module.

de-active = <1>;
hsync-active = <0>;
vsync-active = <0>;
pixelclk-active = <0>;

aneesh.kn · February 2, 2018, 8:23am

1 . We are using Colibri VF61

we have following structure in vf-colibri eval-v3.dtsi

panel: panel {
compatible = “shanghai,tm070rbh10”;
//compatible = “shelly,sca07010-bfn-lnn”;
//backlight = <&bl>; // Removed Back Light to Free PWM - Aneesh K N
power-supply = <&reg_3v3>;
};

Should we use below format?

display: display@0 {
bits-per-pixel = <16>;

    display-timings {
        native-mode = <timing_vga>;
        /* Standard VGA timing */
        timing_vga: 640x480 {
            clock-frequency = <25175000>;
            hactive = <640>;
            vactive = <480>;
            hback-porch = <40>;
            hfront-porch = <24>;
            vback-porch = <32>;
            vfront-porch = <11>;
            hsync-len = <96>;
            vsync-len = <2>;
            hsync-active = <0>;
            vsync-active = <0>;
            pixelclk-active = <0>;
        };
    };

jaski.tx · February 2, 2018, 8:45am

yeah, you just have to adapt the number according to the datasheet of your display.

aneesh.kn · February 2, 2018, 8:48am

Do we have to change any uboot settings

aneesh.kn · February 3, 2018, 4:32am

We are receiving following error when executing make statement

~/linux-toradex$ make vf610-colibri-eval-v3.dtb
DTC arch/arm/boot/dts/vf610-colibri-eval-v3.dtb
Error: arch/arm/boot/dts/vf-colibri-eval-v3.dtsi:227.14-23 syntax error
FATAL ERROR: Unable to parse input tree
make[1]: *** [arch/arm/boot/dts/vf610-colibri-eval-v3.dtb] Error 1
make: *** [vf610-colibri-eval-v3.dtb] Error 2

jaski.tx · February 5, 2018, 8:54am

which branch did you use to compile? Can you send a git diff log?

aneesh.kn · March 14, 2018, 4:20am

We Did Following Steps

Cnaged added Densitron Structure to panel-simple.c (Attached File)
Made Panel as Densitron in vf-colibri-eval-v3.dtsi (Attached File)
We Updated zImage and Device Tree as mentioned in link Build U-Boot and Linux Kernel from Source Code | Toradex Developer Center
But the Screen we got is getting shifted unevenly(Attached File)

link text

jaski.tx · March 14, 2018, 8:25am

hi aneesh

I cannot open your jpeg images, how did you create them?

aneesh.kn · March 14, 2018, 12:58pm

Please Check These Image Fileslink text

jaski.tx · March 15, 2018, 4:04pm

can you send the dmesg log in a file?

type fbset in the console and send the output please?

aneesh.kn · March 16, 2018, 5:39am

mode “800x480”
geometry 800 480 800 480 24
timings 0 0 0 0 0 0 0
accel true
rgba 8/16,8/8,8/0,0/0
endmode

jaski.tx · March 16, 2018, 3:29pm

you should use either device tree changes or changes in panel-simple.c

For the panel-simple.c changes you should add the DE flags in configuration too.

static const struct drm_display_mode tpk_f07a_0102_mode = {
	.clock = 33260,
	.hdisplay = 800,
	.hsync_start = 800 + 40,
	.hsync_end = 800 + 40 + 128,
	.htotal = 800 + 40 + 128 + 88,
	.vdisplay = 480,
	.vsync_start = 480 + 10,
	.vsync_end = 480 + 10 + 2,
	.vtotal = 480 + 10 + 2 + 33,
	.vrefresh = 60,
        .flags = DISPLAY_FLAGS_DE_HIGH,
};

deepakrajpoot · October 21, 2019, 12:25pm

I am also facing this issue with imx6. I have looked in imx6ull-colibri-eval-v3.dtsi. Kindly help where to change for 7" resistive touch lcd. I think to EDT ET070080DH6 data. and how enable DE mode from dtsi file. LCD timing details attached link text

,Hi i am also facing same issue with imx6. i have looked imx6ull-colibri-eval-v3.dtsi file, but and where i have to change. kindly support.