LCD / LVDS Interface for Raspberry Pi

[kasperl]

Just cross-posting this here in case people are following this thread but not the rest of the forum.

Gert has confirmed in [1] that the connectors _are_ present on the production boards. Now, I'm not sure when pinouts and/or drivers are available, but as far as image data is concerned this can be made plug and play. Power, of course, isn't that easy, but nothing a USB cable (or three) and a hub can't solve.

[1]: http://www.raspberrypi.org/for.....e-2#p48449

[zydeco100]

Well, that's good news that the connectors will be on there.  I'll be interested to see if the necessary signals are all brought out on those pins.

Power will be a problem that can't be solved by a USB cable or hub.  USB ports are current-limited to a very small amount and if the 5V bus on the Rpi is fuse-limited to 1A then any kind of attached LCD w/backlight will need it's own power supply.

[BigAl1452]

Every ones looking for a "dedicated" screen for the Pi.  I know its aimed at "Education/kids market" and therefore the choice of HDMI or Video Output to match whats at home.  I"m no programmer and do not have the technical training to "hot wire" an LCD screen onto the Pi.

I"ve ordered my Pi, (it will be a long wait till July/August!) in the mean time I"ve put together a little 7" screen from an old Kodac LCD Picture Frame and mounted a cheap A/D Controller Board on the back. I"ve ordered a USB board for the 4wire touch screen. The A/D Board has a Video Input (plus a VGA Input but I don"t need that!)

Total costs to date £16.52 for A/D Board + £6.99 for USB Board.  That includes postage!.  That"s a BIG difference compared to the likes of Xenarcs STG£230.

I"ll be starting some programming later to see what signal come from the Touch Screen via the USB.



Uploaded with ImageShack.us

[dan3088]

I also came to the conclusion that a 4 wire touch screen would be the most cost effective way of adding touch to the pi. However the drivers are beyond my expertise. If you manage to get this working I would be very interested in getting the software as well every one else I suppose.

[kghunt]

I think a good place to start would be to an old iPod display connected as it would be enough to see the command line and run graphics for testing purposes when not connected via ssh. Not to mention they are 5 quid off eBay.

[tg_harris]

BigAl1452 said:


Every ones looking for a "dedicated" screen for the Pi.  I know its aimed at "Education/kids market" and therefore the choice of HDMI or Video Output to match whats at home.  I"m no programmer and do not have the technical training to "hot wire" an LCD screen onto the Pi.

I"ve ordered my Pi, (it will be a long wait till July/August!) in the mean time I"ve put together a little 7" screen from an old Kodac LCD Picture Frame and mounted a cheap A/D Controller Board on the back. I"ve ordered a USB board for the 4wire touch screen. The A/D Board has a Video Input (plus a VGA Input but I don"t need that!)

Total costs to date £16.52 for A/D Board + £6.99 for USB Board.  That includes postage!.  That"s a BIG difference compared to the likes of Xenarcs STG£230.

I"ll be starting some programming later to see what signal come from the Touch Screen via the USB.


Nice!  You wouldn't have a howto on how you did that, along with model numbers for the components you used, do you?

Me, all I want is something inexpensive I can use to read ebooks and listen to my music collection.

[BigAl1452]

tg_harris said:


BigAl1452 said:


Every ones looking for a "dedicated" screen for the Pi.  I know its aimed at "Education/kids market" and therefore the choice of HDMI or Video Output to match whats at home.  I"m no programmer and do not have the technical training to "hot wire" an LCD screen onto the Pi.

I"ve ordered my Pi, (it will be a long wait till July/August!) in the mean time I"ve put together a little 7" screen from an old Kodac LCD Picture Frame and mounted a cheap A/D Controller Board on the back. I"ve ordered a USB board for the 4wire touch screen. The A/D Board has a Video Input (plus a VGA Input but I don"t need that!)

Total costs to date £16.52 for A/D Board + £6.99 for USB Board.  That includes postage!.  That"s a BIG difference compared to the likes of Xenarcs STG£230.

I"ll be starting some programming later to see what signal come from the Touch Screen via the USB.


Nice!  You wouldn't have a howto on how you did that, along with model numbers for the components you used, do you?

Me, all I want is something inexpensive I can use to read ebooks and listen to my music collection.


Heres the best I can do;

- The 7" LCD  screen was from a Digital Photo Picture Frame. (there was no brand name on it.

- The 7" screen had the following details on it Innolux 7", Model No. AT070TN92.

- When I Googled the Model No. I got the following; 50pin, 800x480LED display (thats all I needed to find an A/D Controller Driver Board)

- Searched on ebay for a Driver Board and found an ebay shop called njytouch. They had a Driver Board!.

- An e-mail confirmed the part no. HCR-N1 and programming setup.

- The USB 4Wire Board was got from ebay.

- When the parts arrived it was a simple plug and play!

I found that once you get the screens Model No. these people at njytouch can advise and match a Driver Board to match.  I work in the security industry, mainly CCTV and since talking to these people I've ordered quite a few parts.  (I have installed "Pictures-in-Wall Screens" which are switched to a CCTV input for Access/ Surveillance).

They do all the work in programming the boards to match the Screen. I don't have the time.  The good thing is they can do boards for most sizes. I've got boards for 3.5", 7", 10" and 19".

I know this will kill the die-hard programmers, put I have not got a clue on LVDS programming. (if anyone knows a good site to learn from I would be delighted to try!)

Heres the ebay links: http://www.ebay.com/itm/LCD-Co.....690wt_1140

http://www.ebay.co.uk/itm/4-Wi.....150wt_1110

[olivernz]

So, still waiting for my RPi but i have a Macbook Pro 13" i5 with a broken mainboard, that I want to put my RPi in. What I need is a hint to what LVDS I need to drive the screen. Keyboard and touchpad seem to be USB. We'll see how far i get.

Oliver

[floppyjoe]

I will be using an Archos 5 IMT it's a 5" touch screen media tablet with a 120gb hard drive.

The IMT runs  on embedded Linux, using the RPI with xbmc I should have a nice media streamer. Looking forward to experimenting with various flavours of linux on my PI.

thought I would have received an RPI by now, but thats just PI in the sky.

[BertM]

Just in case anyone is still wondering about the DSI interface, the connectors are populated. Two data lanes + one clock lane are exposed to the connector, as can be read in the schematics.

[ChalkElec]

Hi everyone, after long development and mistakes that we encounter during the LVDS interface development, we finally got it done! Our LCD/LVDS interface for Raspberry Pi is finally launched!
Check out our video on our HDMI-LVDS in action http://www.youtube.com/watch?v=llC-gVw1wBs
We are very excited that we got our first batch of production sold out in 10mins and now we are taking pre-sales order for our 2nd batch production. The pre-sales order comes with small discount to compensate for your waiting time.
Check out our shop below:
http://www.chalk-elec.com/?page_id=1280 ... t=priceAsc

[ChalkElec]

We found that our previous video on the LCD/LVDS interface for Raspberry Pi has cause some confusion to our fans out there. Therefore, we have decided to redo another one for clear up the situation.
http://youtu.be/Sx_vFY7ioEQ
Enjoy !!

[jorabo]

Hi,
we are currently developing a new HDMI2LVDS adapter for PI,
have a look at our Prototype
Currently working with 6,5" AUO Display. AUO_G065VN01_V2

Will be deliverable and buyable on ebay soon.

Jonny

[mamitsch]

Is this a universal hdmi2lvds converter? I'd like to buy one which is usable not only with PI but also with other developer boards.

Thanks in advance

Marcus

[abishur]

looking nice! Do you have a list of known incompatible screens? When do you expect (hope) this updated board to hit the stores?

[jorabo]

Is this a universal hdmi2lvds converter? I'd like to buy one which is usable not only with PI but also with other developer boards.

Thanks in advance

Marcus

Hi @all,

final release is nearly done, pcb factory is working to build the last preview release
The current release should work with every 1ch lvds display in connection with PI.
(testing with odroid later on)
Backlightsettings can be done by connecting 2 contacts on the pcb to GND,settings are stored in AVR

You need to write a working edid.dat to your boot dir. And you need to configure your config.txt.

For this AUO display you need the following entries to config.txt:
framebuffer_depth 24 #looks better than default 16
hdmi_edid_file=1 #get hdmi info from file
hdmi_force_hotplug=1 #you dont really need this entry, but if you like to reconnect your display to
#a running PI -> you'll need it
hdmi_group=2 #Resolution settings ....look at elinux.org
hdmi_mode=4 #Resolution settings ....look at elinux.org



You dont have to invent the whole edit.dat,

http://www.raspberrypi.org/phpBB3/viewt ... 21#p246821

this works great !

my edid.dat for 640x480 (AUO) is attached (unzip)

[jorabo]

looking nice! Do you have a list of known incompatible screens? When do you expect (hope) this updated board to hit the stores?

Hi,
should get the latest pcb version next week for testing.

if it works fine...give our pcs factory max 4 weeks to build the first 250 pcs

Regards,

Jonny

[abishur]

Backlightsettings can be done by connecting 2 contacts on the pcb to GND,settings are stored in AVR

Does this mean it will be a permanent backlight setting when you connect the contact to ground, or is this to enable dynamic control of the backlight?

[jorabo]

Backlightsettings can be done by connecting 2 contacts on the pcb to GND,settings are stored in AVR

Does this mean it will be a permanent backlight setting when you connect the contact to ground, or is this to enable dynamic control of the backlight?

The backlight ist switched on/off bye the PI (in addition, there is a avr-pin for forced poweroff), but with these pins, you can make the backlight bright or dark. in steps of apx. 10%.
This setting ist stored in the AVR (EEprom).

I'll provide the source for the AVR at the time of first delivery (hopefully without errors).

[jorabo]

HDMI->LVDS V2.0 release in production !

Hi @all,
the final release is in production now.
I'm currently working on the documentation and pinout description.
I'll post the final price as soon as i get it from our pcb-factory.

Package contents will be:
HDMI ->LVDS Board,
25 cm LVDS Cable
4x 4pin-Micromatch connectors
2x 6pin-Micromatch connectors

Supply voltage 5V to 9V DC, (9V if you want to connect your backlight-LEDs directly to the board)

[jorabo]

Sorry, for the very short documentation

Code: Select all

$crystal = 8000000
$regfile = "ATtiny44.DAT"

Cec Alias Pina.0
Config Cec = Input
Porta.0 = 0                                                 'Pullup aus


Force_off Alias Pina.1
Config Force_off = Input
Porta.1 = 1                                                 'Pullup ein



Heller Alias Pina.2
Config Heller = Input
Porta.2 = 1                                                 'Pullup ein


Dunkler Alias Pina.3
Config Dunkler = Input
Porta.3 = 1                                                 'Pullup ein


Onoff Alias Portb.1
Config Onoff = Output

Puls Alias Portb.2
Config Puls = Output

Led Alias Portb.0
Config Led = Output
Portb.0 = 1


Onoff = 0                                                   'Display aus
Dim Ledcnt As Integer
Ledcnt = 0


Dim Rest As Integer
Declare Sub Ledslow()                                       'not used
Declare Sub Ledfast()                                       'not used

Dim X_puls As Eram Byte

Config Timer0 = Pwm , Prescale = 1 , Compare A Pwm = Clear Down

If X_puls < 50 Then

    Pwm0a = 150                                             'Mittlere Helligkeit als default
    X_puls = 150                                            'speichern

End If

If X_puls > 250 Then

    Pwm0a = 150                                             'Mittlere Helligkeit als default
    X_puls = 150                                            'speichern

End If



   Pwm0a = X_puls


Do

If Ledcnt <= 1000 Then
Ledcnt = Ledcnt + 1
Else
Ledcnt = 0
End If

Waitms 100

 If Force_off = 0 Then

    Onoff = 0

 Else

   If Cec = 1 Then

      Onoff = 1

      If Heller = 0 And Pwm0a <= 240 Then
           Pwm0a = Pwm0a + 10
           X_puls = Pwm0a
      End If

      If Dunkler = 0 And Pwm0a >= 50 Then

         Pwm0a = Pwm0a - 10
         X_puls = Pwm0a
      End If


   Else


      Waitms 200                                            'Wenn nach 200ms immernoch low Display off
      If Cec = 0 Then
      Onoff = 0
      End If


    End If
  End If
Loop


End

Sub Ledslow()

Rest = Ledcnt Mod 200
If Rest = 0 Then
    Toggle Led
End If

End Sub

Sub Ledfast()


Rest = Ledcnt Mod 200
If Rest = 0 Then
    Toggle Led
End If

End Sub

[jorabo]

Hi,

first release of a documentation for the HDMI-LVDS V2.0 available for download:
http://www.terminalschmiede.de/HDMI-LVD ... ocV0.1.pdf


Jonny

[harryweb]

Hi Jorabo,

It will be a great idea to tell us or give us what LCD panel are compatible (name, datasheet, where to find ... good reseller...)

For personnal or company information waiting for real cheap screen to plug for Raspberry

May be a site/blog... ?

Regards

[jorabo]

Hi Jorabo,

It will be a great idea to tell us or give us what LCD panel are compatible (name, datasheet, where to find ... good reseller...)

For personnal or company information waiting for real cheap screen to plug for Raspberry

May be a site/blog... ?

Regards

Hi,

normaly all 8 bit single channel lvds displays should work out of the box. 6 bit displays not tested...

I have successfully tested the following displays till now:

AUO : G065VN01 V2 ~ 135 €/unit at msc-ge
AUO : G084SN05 V9
NEC: NL6448BC20-21D (additional Inverter needed)

I'll keep on testing every display, i can get

[DrPinball]

For LED backlit screens is an LED driver needed or is this included on the board?