Interfacing

[SOLVED] connect 10" display to LVDS interface (CON2)

11 13505
Edited by Sebastian at 2014-10-14 03:31

Hi everyone!

I want to connect the EJ101IA-01G display to my BananaPi which runs with Bananian Linux.
You can find the datasheet of the display attached to this post!

The provided driver board of the display works fine with the HDMI output of the Pi but since the display uses a 40 pin FPC I want to connect it directly to the LVDS connector of the Pi.
Comparing the BananaPi pinout (e.g. on Bananapi.org ) with the pinout of the display (on page 2 and 3 in the datasheet) you can see that it can't be connected one-to-one. Keeping that in mind I soldered the pins as follows:

Pin Display Symbol Display CON2 Pin BananaPi Pin Name BananaPi
8 Rxin0- 11 LCD0-D1
9 Rxin0+ 9 LCD0-D0
11 Rxin1- 15 LCD0-D3
12 Rxin1+ 13 LCD0-D2
14 Rxin2- 19 LCD0-D5
15 Rxin2+ 17 LCD0-D4
17 RxCLK- 23 LCD0-D7
18 RxCLK+ 21 LCD0-D6
20 Rxin3- 27 LCD0-D9
21 Rxin3+ 25 LCD0-D8

I connected LED_PWM to PWM0 as well.

Furthermore, I used external power supplies for the different voltages such as the 5V for the LED backlight and the 3.3V for the logic etc. The values can be found in the display datasheet on page 6.

To further get the display and Pi operate synchronously I edited the script.bin of the Pi as follows:
(The timing of the display can be found in the datasheet on page 9.)

Concidering the driver constraints:
lcd_ht = (lcd_hbp+lcd_x+4)
lcd_vt = (lcd_vbp+lcd_y+2)*2
  1. [disp_init]
  2. disp_init_enable = 1

  3. [lcd0_para]
  4. lcd_used = 1
  5. lcd_x = 1280
  6. lcd_y = 800
  7. lcd_if = 3
  8. lcd_dclk_freq = 70
  9. lcd_hbp = 160
  10. lcd_ht = 1444
  11. lcd_vbp = 23
  12. lcd_vt = 1650
Copy the Code
Apparently, after all these changes the display doesn't work like it should. I already measured the data inputs and the clock with an oscilloscope and didn't find any malfunctions. The clock is fine and the data is like it's supposed to be.
Did I miss any adjustments?
Do I have to somehow enable the CON2 connector first or set the connection as primary video output? (Which I thought I did while changing the script.bin ..)

I am certainly grateful for help or any advice!!

Thank you!

Seb

EJ101IA-01G spec.pdf

349.01 KB, Downloads: 224

Display spec

hawok  
try to set this values in script.bin disp_init section

[disp_init]
disp_init_enable = 1
disp_mode = 0
screen0_output_type = 1
screen0_output_mode = 4
screen1_output_type = 1
screen1_output_mode = 4

Reply 2# hawok


   Hi hawok,

thanks for your reply.
I'll give it a shot and I'll get back to you as soon as possible.


Seb

try to set this values in script.bin disp_init section

[disp_init]
disp_init_enable = 1
disp_mode = ...
hawok Posted at 2014-10-10 08:38


Hi Hawok!
I changed the values you mentioned but sadly that didn't do the job.
Do you have any other suggestions?

Seb

I finally solved my problem.
Again thanks to Hawok for his advice and the LeMaker support for their effort!!

For everyone else:
I needed to load the LCD driver by modifying the /etc/modules file as follows:
$ vim /etc/modules
   #For RPi
   #snd-bcm2835

   #For SATA Support
   #sw_ahci_platform

   #Display and GPU
   lcd
   #hdmi
   ..

Seb

Could you tell what OS you're using ?

Chalk-elec has touchpanels, but sells them with an hdmi-to-lvds-converter.
I have such a 10" display but it does not work with android with the convertor. So I would like to try it without the convertor.

I'm using Bananian Linux on my Pi.
I don't have any experience working with android, sorry.

rhradec  
Edited by rhradec at Fri Oct 31, 2014 16:45

I have a DLP Projector that I also want to connect through LVDS...

Although I have the exact same pins, mine has an extra couple pins Rxin4+/- (named RE_IN_P/RE_IN_N) !

Should I ignore those?

Screen Shot 2014-10-31 at 3.48.34 PM.png


this is the datasheet of mine:
http://www.ti.com/lit/ds/dlps031a/dlps031a.pdf

eggert  
Hi Seb,
you wrote you use external power for the different voltages means this you supply 5 voltages externally (2.5v, 8.2v, 22v, -7v and 3.3v) ?
Do you use something like 5 LM2596 circuits?  
Do you know a simple way to get the -7v?

Thorsten

Edited by Sebastian at Mon Nov 10, 2014 08:53

Hi Thorsten,

I used 15V input for my circuit board. In order to provide the different voltages for the display I had to use voltage converters such as the ICL 7660 Converter which supplied the desired -7V.

Seb

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