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DrWizard

Big LCD display

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I was wondering if it would be possible and feasible to drive a big LCD display using a Tiva C board.  Not tooooo big or hi-res, I was thinking of reusing one from an ancient laptop.  Say 13" with a resolution of 1024 X 768.  Has anyone done this?

 

I have several such old displays just lying around.  I found datasheets for each of them, but they are so full of acronyms and abbreviations that it was all greek to me.  So I'm not too clear on how the controller interfaces work or how much work it is to drive one.

 

I'm not wanting to do any fancy graphics or fast animation.  Mainly just display a fair bit of text, in fonts large enough to see from a distance.

 

 

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If you still have the ancient laptop attached, then yes you could probably do this.

Set up communications between the Tiva C and the laptop processor 

(if laptop doesn't have USB port, could use serial port (have to shift levels)).

 

If the laptop part no longer exists/works then you have a much larger challenge - finding a driver for the LCD.

I understand that some recent laptops have sem-istandard drivers and there is some possibility of getting a driver board that will work with it.

http://hackaday.com/2014/02/06/turning-a-broken-laptops-lcd-into-a-fancy-monitor/

http://makezine.com/2011/09/06/33-board-turns-your-bare-lcd-into-working-monitor/

As far as I know such controller boards usually use a VGA or DVI or such interface (so would still have a way to go to drive it with a Tiva C).

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On that topic, the fleeting thought occurred to me... Has anyone produced a simple IC one could drop into a project to drive a VGA display with a text terminal of sorts? Seems like a cool idea. I wanna say someone has done it with the AVR before? Or maybe that was composite out...

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On that topic, the fleeting thought occurred to me... Has anyone produced a simple IC one could drop into a project to drive a VGA display with a text terminal of sorts? 

 

How about an Arduino? ;-)

http://hackaday.com/2013/03/29/avr-vga-generator/

http://hackaday.com/2010/11/23/vga-interfacing-avr-microcontrollers/

 

In a related vein - here is doing VGA with an STM32F4

http://forum.stellarisiti.com/topic/65-stm32f4-discovery-generating-vga-signals/

 

And the following repository has a tantalizing title (I haven't found any explanation to go with it, so no idea what state it is in).

https://github.com/yuvadm/stellaris/tree/master/boards/ek-lm4f120xl/stellaris-vga

 

Or you could use an ISA VGA card

http://tinyvga.com/avr-isa-vga

(If you look at the site this is on, looks like they may have produced the IC in question - though a bit pricey.)

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The LCD displays from laptops are do not have a standard VGA or DVI type interface, but rather require some external circuitry to vertically and horizontally scan the screen and clock in the pixels.  They do not even include a frame buffer.  Precisely how this is done though, I do not understand.  As I mentioned above, the datasheets are full of acronyms and abbreviations.  I suspect however, that someone must make some intermediate interface chips that provide a frame buffer and a simple way to send data to it.  That's how the smaller, lower res ones that come on the cheap shields and booster packs work.  Example: The Ilitex ili9341 controllers used on the 2.2" Color LCD Booster Pack which drives a 240 X 320 LCD display using a 4-wire SPI interface.  Does anyone know of a similar controller for bigger, higher res displays?

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The LCD displays from laptops are do not have a standard VGA or DVI type interface, but rather require some external circuitry to vertically and horizontally scan the screen and clock in the pixels.  They do not even include a frame buffer.  Precisely how this is done though, I do not understand.  As I mentioned above, the datasheets are full of acronyms and abbreviations.  I suspect however, that someone must make some intermediate interface chips that provide a frame buffer and a simple way to send data to it.  That's how the smaller, lower res ones that come on the cheap shields and booster packs work.  Example: The Ilitex ili9341 controllers used on the 2.2" Color LCD Booster Pack which drives a 240 X 320 LCD display using a 4-wire SPI interface.  Does anyone know of a similar controller for bigger, higher res displays?

 

What constraint(s) prevent using something like the LVDS driver board mentioned above along with something like the Tiny VGA?

(space, money, power, ...?)

By the time you are talking full VGA you have a lot of bits to shovel around, not obvious why somebody would have come up with 

an integrated solution that connects that to a low speed interface (serial, etc.).  Not saying they haven't, just not sure why they would.

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If you want to natively drive an LVDS LCD, your best bet is to take a look at some of the ARM Linux single board computers, ie. cubieboard, o-linuxino, or iTeaduino Plus.  I just got an iTeaduino Plus A20 a few days ago, with the intention of using it with an old laptop LCD.  I have a ways to go to figure out custom kernels, drivers, and interface, but it is very doable.  The AllWinner A10/20 and i.MX6 based SBCs all have native LVDS display functionality built in if you can figure out how to use it.  Right now I'm stuck at either needing a custom LVDS cable, or trying to find a supplier for the connector HP uses on the old DV series laptops to attach the LCD.  Unfortunately, the connector is not standard, and is only made by one company out of China and I have had no luck finding a supplier for it short of contacting their US office in Austin and seeing if I can get some samples.

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Just had a couple of other thoughts -

It would not be a one chip solution, but you could also look at the USB to VGA adapters.

Main issue there might be sorting out a driver (if any of them have open source drivers, or enough documentation to do a driver.)

 

Other thought was to look at chips used in photo frames.  Some photo frames are fairly large.  

I don't know whether they use LVDS screens, or some other connection scheme.

The smaller frames I have taken apart typically have multiple chips in them, so don't know if you will find a one chip solution,

or how easy they may be to come by, and how easy to program (i.e. documentation might be scarce).

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