LCD on RevC

GoogleGroups
1

Hey guys, I'm a little lost when it comes down to hardware
communication...could you please give your opinion about the e-mail
below:

"
  Hi, I've read a discussion in which you mentioned the possibility of
attaching 18-bit(6 bit per channel) lcd panels to the beagle...

to keep it simple, is it currently possible to attach an 18-bit lcd
panel to the beagleboard(rev c) through the lcd header (I already
understand about the voltage level difference)?? which dvi_datax is
red, blue and green(there are 24 of them, so I assume it is 8 bit per
channel..)?? if I simply ignore 2 pins per channel would it be ok?

could you please give some explanation??

thanks in advance, every answer I get I'll post in the group "

I'm doing some research in order to buy me an LCD...all the ohter
solutions like Hy-research do not fit my needs, since I want a 7" lcd
(even though it's more expensive than the psp lcd)

thanks a lot,

Saul

2

Yes, Just use the upper 6 bits of each of the 8 bits per color provided. Level shift them and you should be OK.

BEAGLE-------> 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
LCD PANEL–>x x 0 1 2 3 4 5 x x 0 1 2 3 4 5 x x 0 1 2 3 4 5

Of course you need the power supplies to provide whatever voltages you need for for the display panel itself, including the back light.

Gerald

3

thanks a lot

Saul Andrade

4

Thank you very much, When I get the LCD I'll post the results.

When are we having a beagleboard event in Brazil?? ^ ^

would be fun,

Saul Andrade

5

Saul escreveu:

Thank you very much, When I get the LCD I'll post the results.

When are we having a beagleboard event in Brazil?? ^ ^

would be fun,

I've answered directly to the email in your signature but looks like you
didn't get it. We can try to organize such an event, what do you think?

s

Adilson.

6

Hi Adilson, my mail here is old, use the new one:
saul.a.andrade@gmail.com

7

and, yes, I would really be satisfied organizing it.

8

This topic is pretty much interesting to me. I'm a newby in linux
programming so ,here my doubts :

- I'm planning to interface an LCD 7" screen to the BeagleBoard
- I can configure the mux with u-boot to get the LCD lines on J4 and
J5
- Should I configure the kernel to have LCD support? What is the right
setting for this? I see some options but apparently I cannot choose
the right ones
- I'll bitbake console-image and get text out on the LCD (hopefully)
- Than I'll use level shifter to boost the line voltage

Moreover ..

I see from the OMAP3530 datasheet that it is possible to configure
serial lines to drive LVDS displays. How can I get kernel support for
this? Is it available??

thanks a lot

Fabio

9

LVDS support is not widely supported on the OMAP3530. You also have a TFP410 interface connected to the LCD pins which could prevent it from working as it interferes with the signals. You are also limited to low resolution on these pins at the LVDS interface, so anything past 320x240 is not possible. That would be a waste to drive a 7" display at that resolution. You also need to make sure that if you are using the LCD pins to drive a display, that they be level shifted. The signals are 1.8V only and I don’t know of any display that can handle that.

Gerald

10

Would something like
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-6668-1-ND
help? I haven't tried it but, I believe that should not restrict the
resolutions usable on the screen. Please let me know if I'm wrong, I'm
planning on designing something to that affect. It would be good to
know if it won't work :slight_smile:

Thanks,
--Krishna/.

11

Yes a serializer can do the job, thank you. I used in the past DS90C363 and workedvery well.
But in this case I’ll stick to a level shifted parallel interface first and move to LVDS after I’ve debugged the interface.
So I also understand the OMAP-LVDS is not usable, that’s a pity.

Thanks

Fabio