Author Topic: NHD-7.0-800480EF-ASXN#-CTP with Android Linux  (Read 273 times)

v8dave

  • Jr. Member
  • **
  • Posts: 18
  • Karma: 2
    • View Profile
NHD-7.0-800480EF-ASXN#-CTP with Android Linux
« on: May 12, 2019, 10:08:39 PM »
I am trying to get a NHD-7.0-800480EF-ASXN#-CTP display working with Android and I am unable to get anything to display on the LCD. I've used this same LCD before with a small processor running .NET Microframework with great success, albeit a slow interface.

I am using the following timings and checking with a scope to ensure the wiring is correct, I do see the HSYNC, VSYNC, DEN and CLK on the correct pins.

static struct nxp_lcd wvga_axon = {
   .width = 800,
   .height = 480,
   .p_width = 155,
   .p_height = 93,
   .bpp = 24,
   .freq = 40,

   .timing = {
      .h_fp = 40,
      .h_bp = 88,
      .h_sw = 48,
      .v_fp = 13,
      .v_fpe = 1,
      .v_bp = 32,
      .v_bpe = 1,
      .v_sw = 3,
   },
   .polarity = {
      .rise_vclk = 1,
      .inv_hsync = 1,
      .inv_vsync = 1,
      .inv_vden = 0,
   },
   .gpio_init = nhd_gpio_init,
};

I've tried different settings for the polarity with no success. The kernel code has extra debug to confirm the LCD settings are being applied.

Anyone else been able to make this work?

v8dave

  • Jr. Member
  • **
  • Posts: 18
  • Karma: 2
    • View Profile
Re: NHD-7.0-800480EF-ASXN#-CTP with Android Linux
« Reply #1 on: May 14, 2019, 01:58:33 AM »
I have this working. It was the fact I had only made changes in the kernel source but had to make changes to u-boot.

Now it almost works except for some tearing of the display that is visible on the edges of graphics and on text.

v8dave

  • Jr. Member
  • **
  • Posts: 18
  • Karma: 2
    • View Profile
Re: NHD-7.0-800480EF-ASXN#-CTP with Android Linux
« Reply #2 on: May 24, 2019, 02:13:27 AM »
I currently have something partially working in that the display is more stable but I still get horizontal tearing when anything on the left of the screen displays anything other than black pixels.

I found I needed 22R resistors in the timing signals and reduce the drive current of the RGB lines to the min value.

The hor back porch timing is actually set to 40 which is the setting from the 5.0" LCD and yet the timing for all of the 7.0" LCD's show this to be 88 but with that I get lots of horrible noise on the display.

The attached image shows the LCD in portrait mode so the tearing or line shift is the left if this was landscape (the portrait/landscape issue is another matter but that is in the Android core so I just need a stable LCD first)

 

NHD-7.0-800480EF-34 Controller Board vs NHD-4.3-480272MF-34 Controller Board

Started by EdwinSBoard TFTs

Replies: 1
Views: 5272
Last post July 08, 2014, 09:34:55 AM
by Michael_L
NHD-7.0-800480EF-ASXV#-CTP - "Touch" stopped working on part of LCD

Started by coran21Board TFTs

Replies: 1
Views: 1574
Last post February 19, 2019, 11:20:53 AM
by Sergio_M
NHD-7.0-800480EF-ATXV-CTP step/iges file request

Started by lakshminarayananBoard TFTs

Replies: 1
Views: 4151
Last post July 24, 2015, 11:25:39 AM
by Paul_B
NHD-7.0-800480EF-20 Controller Board and the backlight on a 800x480 LCD Display

Started by dfanslerBoard TFTs

Replies: 1
Views: 6191
Last post July 27, 2015, 10:08:23 AM
by Saurabh_B
MOVED: working with nhd-7.0-800480ef-asxv-t with buildroot framebuffer

Started by Saurabh_BBoard Graphic LCDs

Replies: 0
Views: 2876
Last post November 16, 2017, 08:14:59 AM
by Saurabh_B