Sharp 480x272 LCD LQ043 with PXA270... need LCCR values

I have a reference platform for Windows CE 5.0 based on the PXA270 processor;
the display we'd like to use is the Sharp LQ043, 480x272x24bpp (only using
16bpp)... looks like the PXA270 should be able to do this w/o additional glue
logic.

(LCD Panel spec:
http://www.sharpsma.com/Page.aspx/americas/en/part/LQ043T3DX02/ )

Does anyone have any experience setting the LCCR[0..3] registers for this
display?

I have some values that generate a good looking waveform on the logic
analyzer, but still no display...
LCCR0 003008F9,
LCCR1 0101A1DF
LCCR2 0202250F
LCCR3 0470FF05
My LCLK is 100Mhz.

voidcoder
Tue Feb 06 03:21:40 CST 2007


Interesting, how are you going to get acceptable 24bpp
output from 16bpp color? May be I'm missing something,
but I think the only options are:

- Using 8->24 bpp lookup palette
- Using 24bpp or 32bpp frame buffer


bkeithmoran wrote:
> I have a reference platform for Windows CE 5.0 based on the PXA270 processor;
> the display we'd like to use is the Sharp LQ043, 480x272x24bpp (only using
> 16bpp)... looks like the PXA270 should be able to do this w/o additional glue
> logic.
>
> (LCD Panel spec:
> http://www.sharpsma.com/Page.aspx/americas/en/part/LQ043T3DX02/ )
>
> Does anyone have any experience setting the LCCR[0..3] registers for this
> display?
>
> I have some values that generate a good looking waveform on the logic
> analyzer, but still no display...
> LCCR0 003008F9,
> LCCR1 0101A1DF
> LCCR2 0202250F
> LCCR3 0470FF05
> My LCLK is 100Mhz.
>

bkeithmoran
Tue Feb 06 10:03:01 CST 2007

Wiring the least significant bits of each color to ground will do it. The
color palette will be more granular, but will work just fine.


"voidcoder" wrote:

>
> Interesting, how are you going to get acceptable 24bpp
> output from 16bpp color? May be I'm missing something,
> but I think the only options are:
>
> - Using 8->24 bpp lookup palette
> - Using 24bpp or 32bpp frame buffer
>
>
> bkeithmoran wrote:
> > I have a reference platform for Windows CE 5.0 based on the PXA270 processor;
> > the display we'd like to use is the Sharp LQ043, 480x272x24bpp (only using
> > 16bpp)... looks like the PXA270 should be able to do this w/o additional glue
> > logic.
> >
> > (LCD Panel spec:
> > http://www.sharpsma.com/Page.aspx/americas/en/part/LQ043T3DX02/ )
> >
> > Does anyone have any experience setting the LCCR[0..3] registers for this
> > display?
> >
> > I have some values that generate a good looking waveform on the logic
> > analyzer, but still no display...
> > LCCR0 003008F9,
> > LCCR1 0101A1DF
> > LCCR2 0202250F
> > LCCR3 0470FF05
> > My LCLK is 100Mhz.
> >
>

Paul
Tue Feb 06 10:57:15 CST 2007

Tying them to ground will not give you a very white white (or a black black,
depending on whether ffffff = black or white). You'd be better off tying
the less-significant data bits to more-significant ones so that you are able
to generate 000000 and ffffff, both.

Is that an active matrix display? If so, it should be dead-easy to get the
values right. You just have to get the datasheet for the display, enter the
right values for the front porch and back porch for both horizontal and
vertical, the number of pixels, etc. If it's an active display and you're
getting absolutely nothing, I'd bet that you have the values set completely
wrong. Use a logic analyzer to look at the clock and data signals and make
sure that they match what the display data sheet says they should look like.

Paul T.

"bkeithmoran" <bkeithmoran@discussions.microsoft.com> wrote in message
news:B54B2615-216A-4B3C-9600-CB9661B4E94D@microsoft.com...
> Wiring the least significant bits of each color to ground will do it. The
> color palette will be more granular, but will work just fine.
>
>
> "voidcoder" wrote:
>
>>
>> Interesting, how are you going to get acceptable 24bpp
>> output from 16bpp color? May be I'm missing something,
>> but I think the only options are:
>>
>> - Using 8->24 bpp lookup palette
>> - Using 24bpp or 32bpp frame buffer
>>
>>
>> bkeithmoran wrote:
>> > I have a reference platform for Windows CE 5.0 based on the PXA270
>> > processor;
>> > the display we'd like to use is the Sharp LQ043, 480x272x24bpp (only
>> > using
>> > 16bpp)... looks like the PXA270 should be able to do this w/o
>> > additional glue
>> > logic.
>> >
>> > (LCD Panel spec:
>> > http://www.sharpsma.com/Page.aspx/americas/en/part/LQ043T3DX02/ )
>> >
>> > Does anyone have any experience setting the LCCR[0..3] registers for
>> > this
>> > display?
>> >
>> > I have some values that generate a good looking waveform on the logic
>> > analyzer, but still no display...
>> > LCCR0 003008F9,
>> > LCCR1 0101A1DF
>> > LCCR2 0202250F
>> > LCCR3 0470FF05
>> > My LCLK is 100Mhz.
>> >
>>

bkeithmoran
Tue Feb 06 17:40:01 CST 2007

Yes, the LSBs should be tied to the next-highest-active bit, in the final
rev. For testing, it's okay to have a less-bright display. Being the LSBs,
doesn't have too much effect on the final display.

We have it partially working -- need to tweak some values -- one of the
displays we were using had a crack in the thin film that we didn't notice. We
must have burned hours on that.

When you make the assumption the screen is good, and the logic analyzer
looks good, but still no display, it's very frustrating!

voidcoder
Mon Feb 12 01:56:34 CST 2007


Oh, you are ready for soldering! I thought you want it solved in
software just using some magic PXA LCD controller config ...

>> looks like the PXA270 should be able to do this w/o additional glue
>> logic.


bkeithmoran wrote:
> Wiring the least significant bits of each color to ground will do it. The
> color palette will be more granular, but will work just fine.
>
>
> "voidcoder" wrote:
>
>> Interesting, how are you going to get acceptable 24bpp
>> output from 16bpp color? May be I'm missing something,
>> but I think the only options are:
>>
>> - Using 8->24 bpp lookup palette
>> - Using 24bpp or 32bpp frame buffer
>>
>>
>> bkeithmoran wrote:
>>> I have a reference platform for Windows CE 5.0 based on the PXA270 processor;
>>> the display we'd like to use is the Sharp LQ043, 480x272x24bpp (only using
>>> 16bpp)... looks like the PXA270 should be able to do this w/o additional glue
>>> logic.
>>>
>>> (LCD Panel spec:
>>> http://www.sharpsma.com/Page.aspx/americas/en/part/LQ043T3DX02/ )
>>>
>>> Does anyone have any experience setting the LCCR[0..3] registers for this
>>> display?
>>>
>>> I have some values that generate a good looking waveform on the logic
>>> analyzer, but still no display...
>>> LCCR0 003008F9,
>>> LCCR1 0101A1DF
>>> LCCR2 0202250F
>>> LCCR3 0470FF05
>>> My LCLK is 100Mhz.
>>>