IS possible to use an LCD without controller, on the BBB?

[Karl Longen]

So, I've trashed an old laptop, and I have this nice 13 inch LCD screen that is sitting in my drawer.

I was planning to use it for some project, and I thought that the BBB would be perfect. 

From what I understand, to use the LCD I need a LCD controller, which per se is an inverter and a board that has IN for HDMI or VGA; I've seen some on Ebay.

Altho they are big, they need power, and they are cluttering the display. so I would end up having the BBB plus 3 boards and the LCD.

My question is: is the BBB able to drive an LCD, without the need of the inverter and the LCD controller? I have a 4 inch LCD cape and I see that it uses a board to drive the LCD, so I thought that, since the BBB has an onboard LCD controller, I can just hook up the monitor power and output the BBB to it?

Am I totally out of track?

[Maxim Podbereznyy]

Send a lcd datasheet. We are not fortune tellers

06.10.2013 12:45 пользователь "Karl Longen" <2frikki...@gmail.com> написал:

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[Charles Steinkuehler]

On 10/6/2013 3:45 AM, Karl Longen wrote:
> My question is: is the BBB able to drive an LCD, without the need of the
> inverter and the LCD controller? I have a 4 inch LCD cape and I see that it
> uses a board to drive the LCD, so I thought that, since the BBB has an
> onboard LCD controller, I can just hook up the monitor power and output the
> BBB to it?

It depends on the LCD. The AM335x can directly talk to most panels that
use plain video signals (red, green, blue, and sync signals), you just
need to wire up the connector correctly.

You'll need interface hardware if the LCD panel uses differential
high-speed signaling, and you might need some hardware to drive the
back-light.

Dig up a manual on the LCD panel (or otherwise figure out the pinout)
and see.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Travis Estep]

If this board came from an old laptop, then it will most likely use an LVDS connection. No, the BBB cannot drive that board without a controller board. You'll still be required to find the datasheet to find out how to initialize it. Good luck with that. Out of the 15 or so scrap LCD panels I have from old monitors and laptops, I have found exactly 0 datasheets to go with them.

[garyamort]

On Sunday, October 6, 2013 4:45:05 AM UTC-4, Karl Longen wrote:

So, I've trashed an old laptop, and I have this nice 13 inch LCD screen that is sitting in my drawer.

I was planning to use it for some project, and I thought that the BBB would be perfect. 

From what I understand, to use the LCD I need a LCD controller, which per se is an inverter and a board that has IN for HDMI or VGA; I've seen some on Ebay.

Altho they are big, they need power, and they are cluttering the display. so I would end up having the BBB plus 3 boards and the LCD.

My question is: is the BBB able to drive an LCD, without the need of the inverter and the LCD controller?

The BBB can send LCD control signals.   Laptop Panels generally use LVDS signals so you need to convert them.

http://circuitco.com/support/index.php?title=BeagleBone_LVDS_LCD_Cape is a cape for connecting the BeagleBone White to a LVDS.  Whether or not it would work for the BBB I don't know.  And you still need configuration data for your panel.

[Karl Longen]

Thanks for the reply.

Yes, it is a LVDS; sadly I have no clue about the model of the LCD, since has no identification marks...it is plain white, was in an old macbook white.

Did some research, and they used 3-4 different panels, so it is hard to pinpoint exactly which is it.

So I am basically in need of a LCD controller anyway...I was hoping that the BBB would have some sort of generic programmable controller, so all that you need is to put the right code in memory when booting it, and it would be able to drive the LCD.

The option from Ebay is not that expensive (40 dollars), but it has a bunch of boards and cables...the cape solution seems still huge, but it looks feasible, if I remove the 2 connectors, making it thinner. Altho there is no data whatsoever on that page, that describe how to use it or the specs.

I wish that on the next model of BB, someone will put a programmable LCD controller; you may not use it, but it is great to know that it is there if needed

Thanks for your reply! I am learning a lot. Sometimes I just don't know where to start.

[Karl Longen]

I do not understand your reply; I didn't ask for the numbers of the super ball. Just trying to figure out if it is possible without buying an external LCD controller.

Thanks

[garyamort]

On Sunday, October 6, 2013 7:46:49 PM UTC-4, Karl Longen wrote:

I wish that on the next model of BB, someone will put a programmable LCD controller; you may not use it, but it is great to know that it is there if needed

It HAS a programmable LCD controller.   The tilcdl driver uses the controller.   What it does not have is LCD to LVDS converter built in - most people will want to connect small LCD's directly.  The cape I posted a link to has a LCD to LVDS converter built in to it.

Here is an LCD to HDMI converter:

http://www.chalk-elec.com/?page_id=1280#!/~/product/category=3094861&id=14647633

Basically it converts the LVDS signals to LCD signals and then feeds the LCD signals to a LCD to HDMI converter.

From the same company they have a BBB to LVDS converter:

http://www.chalk-elec.com/?page_id=1280#!/~/product/category=3094859&id=13415465

[Note: the pins carry the LVDS signals, I beleive it comes with a converter to plug the panel into, as seen on this page: http://www.chalk-elec.com/?page_id=1280#!/~/product/category=3094859&id=13727570]

There is also this one: http://www.tincantools.com/Animal-LVDS-Mini.html

Note: the LVDS/LCD conversion chip seems to fluctuate in availability, which also fluctates the cost.  I've seen various LVDS to X adapters ranging in price from 20$ to 80$ over the course of the year.  Based on the fact that all those companies LVDS products are out of stock, I'd assume that currently it is a low availability time.