7in Display for QSB

[mathias]

Hello,

I'm in an pinch right now. I started to work on a project to develop the GUI for an electrical car based on the QSB running Adeneo's android BSP, but I can't get the display I was supposed to be using for this to work. The display is Hitachi's 7.1inch TX18D37VM0APA. I tried virtually every suggestion in this Community to get LVDS to work, made new entries in ldb.c, mx35_loco.c, changed pll4's clockrate, tried all possible combinations of boot arguments, but I still get no image. So I'm starting to think that the problem might be the display itself, or that it is not compatible with ldb, although I can't check that.

So I wanted to ask: does anyone know an 7in display that is definitely known to work with the QSB? Or has anyone had some experience with any of Hitachi's products and ldb and may know what I'm still missing? Any hint would be very appreciated.

Happy Holidays

Mathias

[mathias]

So I found out about this 7in Display: MCIMX51LCD, which is apparently compatible with the QSB, even though it's been developed for another evaluation board. Since I will probably have to make some changes to the android drivers when I get it, I'd like to ask if anyone knows where I can find the timing parameters corresponding to this display?

Best regards,

Mathias

[jimmychan]

On the hardware side, are all the signals connect from the QSB to your LVDS properly? Please check the signals on the QSB's LVDS connector that should match your LVDS display. Please see the QSB-R schematic page 11 the CON 30.

On the BSP side, do you add your LVDS setting in the ldb.c?

If no, please comment out the "XGA" one and then add the new one in the following :

struct fb_videomode mxcfb_ldb_modedb[] = {

{

  "1080P60", 60, 1920, 1080, 7692,

  100, 40,

  30, 3,

  10, 2,

  0,

  FB_VMODE_NONINTERLACED,

  FB_MODE_IS_DETAILED,},

{

  "XGA", 60, 1024, 768, 15385,

  220, 40,

  21, 7,

  60, 10,

  0,

  FB_VMODE_NONINTERLACED,

  FB_MODE_IS_DETAILED,},

};

For the meaning of each parameter, please read the AN3974 (page 44 -- 3.3.1.2 Panel Configuration).

AN3974 : Different Display Configurations on i.MX35 Linux PDK

[mathias]

First of all, thanks for the help! Sorry for the long wait, I wanted to try out a few things before I wrote again. As for the driver, I did the following:

1) I added this entry in both the video_modes[] struct in mx53_loco.c and the mxcfb_ldb_modedb[] struct in ldb.c, replacing the original xga-entry:

// Für Hitachi

    {

     "XGA", 60, 800, 480, 30066,

     215, 40,

     33, 11,

     1, 1,

     FB_SYNC_CLK_LAT_FALL,

     FB_VMODE_NONINTERLACED,

     0,},

2) In ldb.c, I changed the ldb_clk_prate in ldb_fb_pre_setup() and the pll4_rate in mxc_ldb_ioctl() to 231000000.

3) At boot, I enter these commands to change the uboot environment variables:

setenv lvds setenv bootargs \${bootargs} video=mxcdi0fb:RGB666,XGA di0_primary ldb=di0

setenv set_display run lvds

save

boot

The pdf you showed me convinced me that I'm doing the right thing, and that the problem is probably a hardware one. I already had a custom cable, since the display requires a 20-pin connector:

QSB Connector J9           - TX18D37VM0APA Connector CN1

Pin01: LCD_BLT_EN        -

Pin02: 3V2                       - Pin01: VDD

Pin03: 3V2                       - Pin02: VDD

Pin04: 3V2                       -

Pin05: DISP0_CONTRAST-

Pin06: I2C2_SCL               -

Pin07: I2C2_SDA              -

Pin08: TX0_N                   - Pin05: IN0-

Pin09: TX0_P                   - Pin06: IN0+

Pin10: GND                     - Pin07: VSS

Pin11: TX1_N                  - Pin08: IN1-

Pin12: TX1_P                  - Pin09: IN1+

Pin13: GND                     - Pin10: VSS

Pin14: TX2_N                  - Pin11: IN2-

Pin15: TX2_P                  - Pin12: IN2+

Pin16: GND                    - Pin13: VSS

Pin17: CLK_N                 - Pin14: CLK IN-

Pin18: CLK_P                  - Pin15: CLK IN+

Pin19: GND                     - Pin16: VSS

Pin20: AUX_PWR            -

Pin21: AUX_PWR            -

Pin22: GND                     - Pin03: VSS

Pin23: GND                     - Pin04: VSS

                                         Pin17: IN3-

                                         Pin18: IN3+

                                         Pin19: VSS

Pin24: 5V                       -

Pin25: 5V                       -

Pin26: 5V                       -

Pin27: I2C3_SCL            -

Pin28: I2C3_SDA           -

Pin29: DISP0_RD          -

Pin30: N/C                    -

I left Pin20 open so that the backlight stays on all the time, as soon as I get it to work I plan to connect it to Pin1 of J9. I checked the signals with an oscilloscope in the display's side of the cable, and everything looks alright.

Still, I get no image. That is why I'd like to ask again for finding out where I'm wrong, or trying to find an alternative display that is known to work with the QSB.

Many thanks,

Mathias