Dual LCD support

Dual LCD support

Post by Scott Derric » Thu, 09 Jan 2003 12:40:01



I need a 3.5" embedded  system board that can display to two LCD's.   Each
LCD will display different information.

Kronton's specs and some others mention Dual CRT or Dual LCD support, is
this what they mean or are they talking about driving two LCD's with the
same data?

Also does Linux support dual video output? Anybody done this that can point
me to a source for coding or design information on how to do this?

thanks,

Scott

---
They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety. - Benjamin Franklin
---

 
 
 

Dual LCD support

Post by Mark » Thu, 09 Jan 2003 19:43:43


must they both be VGA feeds  ? would be easy to find a board that had 1 VGA
and you could drive another LCD with I2C or similar.  Just a thought

Mark


Quote:> I need a 3.5" embedded  system board that can display to two LCD's.   Each
> LCD will display different information.

> Kronton's specs and some others mention Dual CRT or Dual LCD support, is
> this what they mean or are they talking about driving two LCD's with the
> same data?

> Also does Linux support dual video output? Anybody done this that can
point
> me to a source for coding or design information on how to do this?

> thanks,

> Scott

> ---
> They that can give up essential liberty to obtain a little temporary
> safety deserve neither liberty nor safety. - Benjamin Franklin
> ---


 
 
 

Dual LCD support

Post by Lewin A.R.W. Edwar » Thu, 09 Jan 2003 23:35:36


Quote:> Kronton's specs and some others mention Dual CRT or Dual LCD support, is
> this what they mean or are they talking about driving two LCD's with the
> same data?

I haven't yet found an embedded board that had two physical video
chips on it, and I wouldn't expect to find one in a 3.5" biscuit form
factor. However there are a couple of chipsets that can drive two LCDs
at once (with different data) and quite a few that can drive LCD and
CRT with different data. If you're willing to make one of your LCDs an
off-the-shelf analog LCD monitor, I think it will expand your range of
candidate SBCs quite a bit.

Quote:> Also does Linux support dual video output? Anybody done this that can point
> me to a source for coding or design information on how to do this?

Well, "Linux" per se doesn't know or care about multiple display
surfaces. If you are using framebuffer memory directly, then you just
poke your image into the memory for the requisite display surface. If
you are using XFree86, then it is possible to get things working in
multi-headed designs, this is what Xinerama is all about.
 
 
 

Dual LCD support

Post by Scott Derric » Fri, 10 Jan 2003 10:03:45


I think I will just have to add another video card  to the stack to drive
two seperate LCD's.

I did find an embedded video card with two complete graphic pipelines, $2K+
Woohee!!!    That's more than my total cost for the whole system!

thanks.

Scott

--

---
They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety. - Benjamin Franklin
---



Quote:> > Kronton's specs and some others mention Dual CRT or Dual LCD support, is
> > this what they mean or are they talking about driving two LCD's with the
> > same data?

> I haven't yet found an embedded board that had two physical video
> chips on it, and I wouldn't expect to find one in a 3.5" biscuit form
> factor. However there are a couple of chipsets that can drive two LCDs
> at once (with different data) and quite a few that can drive LCD and
> CRT with different data. If you're willing to make one of your LCDs an
> off-the-shelf analog LCD monitor, I think it will expand your range of
> candidate SBCs quite a bit.

> > Also does Linux support dual video output? Anybody done this that can
point
> > me to a source for coding or design information on how to do this?

> Well, "Linux" per se doesn't know or care about multiple display
> surfaces. If you are using framebuffer memory directly, then you just
> poke your image into the memory for the requisite display surface. If
> you are using XFree86, then it is possible to get things working in
> multi-headed designs, this is what Xinerama is all about.

 
 
 

Dual LCD support

Post by Michiel Roo » Sat, 11 Jan 2003 00:02:53



> I think I will just have to add another video card  to the stack to drive
> two seperate LCD's.

> I did find an embedded video card with two complete graphic pipelines, $2K+
> Woohee!!!    That's more than my total cost for the whole system!

I don't know if this was already mentioned but for SGI workstations you can buy
a MCO (multichannel option). This allows one framebuffer to drive multiple
monitors, each with a different image on it. I think they do this by driving
each monitor at half the refresh rate it normally runs and then displaying one
half of the images on one monitor and the other half on the second monitor. So
with the framebuffer running at 120Hz, you can have 2 60Hz displays with each
screen refresh displayed on another monitor. There's probably also a buffer
inside the MCO box to reduce flicker (I think they can drive up to 6 monitors).

  greetings,
   Michiel

 
 
 

Dual LCD support

Post by Lewin A.R.W. Edwar » Sat, 11 Jan 2003 00:20:55


Quote:> I think I will just have to add another video card  to the stack to drive
> two seperate LCD's.

BTW: A (not uncommon) wrinkle is to take a board that supports
dual-scan LCDs and run two single-scan displays off it.....
 
 
 

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Any info would be great.  Please help me on this one.  No one I know
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