Re: [Gumstix-users] Using Samsung 800X480 LCD with Palo 43

[gumstixdude <alp...@gm...>]

I bought one of these displays also this afternoon so looks like we're in
this together :) I wonder if powering only one of the sets of LED backlights
results in only half of the screen being lit or the whole screen being lit
at half of the maximum brightness. If it's the latter and you don't need the
screen too bright, that would be a convenient way to solve our problem. 



gnmckinney wrote:
> 
> Yes - From the spec sheets they are both 45-pin 0.5-mm connectors but
> carry different part numbers - I have not looked (yet) to see what the
> actual difference is.
> 
> As for the LED backlight circuit - it looks like there are two strings of
> seven LED's that comprise the backlight system for this LCD display.  I am
> looking at what (if any) changes would need to be done to power both
> strings by the current LED circuit on the Palo board.  I think it may be
> possible to just connect the two strings in series then adjust the
> feedback resister to increase the current somewhat but until I receive the
> LCD display I ordered I really can not say what will be needed.  I do
> know, from the Palo schematics that pin 42 and 43 of the LCD connector are
> the current LED connections for the Samsung LCD sold by Gumstix - the LCD
> display mentioned in this thread also uses pins 44 & 45 for the second LCD
> string and are currently not connected to anything.  To allow a serial
> connection of the LCD strings I will need to modify the connections on the
> LCD connector (basically cut the trace to pin 43 and fly-wire it to pin 45
> then connection pin 43 and 44 together to connect the two LED strings in
> series).
> 
> I will post results as I go so others may follow (or not) what is done
> (grin).
> 
> In the mean time I am looking at what needs to be changed software/kernel
> wise to get the display resolution setup correctly for the 800X480 display
> - any suggestions would be appreciated - I am more hardware oriented than
> software oriented (more touchy touchy than thinky thinky - grin).
> 
> gm...
> 
> 
> 
> gumstixdude wrote:
>> 
>> Aren't they both 45 pin connectors? Hopefully that means they will work.
>> What will need to be done to get the second LED string powered? 
>> 
>> 
>> 
>> gnmckinney wrote:
>>> 
>>> In looking at the specs and wiring it looks like it may work - of course
>>> you will need to change the resolution of the display in the kernel and
>>> possibly in the uboot variables (check the forums for how this is done
>>> as there is a great deal about it there).
>>> 
>>> I decided to order one of the displays to see if it will indeed work -
>>> I, too, want more resolution than the lcd panel offered by Gumstix and
>>> this may be the way to do it - the Palo board has all of the interfacing
>>> needed - now to just get the slight differences resolved (the panel you
>>> listed has two led strings so power has to be configured for the second
>>> string and there is a PWRSEL signal (pin-35) on the Gumstix lcd that is
>>> not on the panel you spec'ed out.  Like I said - minor differences.  If
>>> the actual connectors match these issues are very trivial indeed (grin).
>>> 
>>> gm...
>>> 
>>> 
>>> gumstixdude wrote:
>>>> 
>>>> Hello,
>>>> 
>>>> I want to have a higher resolution display than the one offered by
>>>> Gumstix. If I try to use a Samsung LCD with touchscreen with a
>>>> resolution of 800x480, will it work? 
>>>> 
>>>> Here is the link to the display:
>>>> 
>>>> http://cgi.ebay.com/4-8inch-TFT-LCD-Module-800x480-LMS480KF02_W0QQitemZ300309948034QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item45ebde2682&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A2%7C294%3A30
>>>> 
>>>> Thanks,
>>>> 
>>>> Gumstixdude
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 

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