Two different Resolution LCD on PXA270 platform

Hi,

I am currently working on a project that involve two different resolution TFT
LCD. The platform using PXA270 CPU, and the LCDs are connected through
multiplexer to the PXA LCD controller.

The platform is running WINCE OS, and is able to boot up with either one LCD.

Now i would like to integrate two LCD into the OS.

As i know, WINCE5.0 does not support dynamically change of display resolution
(correct me if i wrong).

Do you guys have any other ideas to implement the dynamic change of display
resolution?

Best regards,
James Cool

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Valter
Fri Mar 28 01:12:42 PDT 2008

"JamesCool via PocketPCJunkies.com" <u42351@uwe> wrote in
news:81d00c26208a6@uwe:

> Hi,
>
> I am currently working on a project that involve two different
> resolution TFT LCD. The platform using PXA270 CPU, and the LCDs
> are connected through multiplexer to the PXA LCD controller.
>
> The platform is running WINCE OS, and is able to boot up with
> either one LCD.
>
> Now i would like to integrate two LCD into the OS.
>
> As i know, WINCE5.0 does not support dynamically change of display
> resolution (correct me if i wrong).
>
> Do you guys have any other ideas to implement the dynamic change
> of display resolution?

You may be able to support resolution change by rotating the display
two times.
You rotate the display 90 degrees and then rotate it back, changing
the resolution in the process.
Obviously you should change your driver to support this "trick" (it
should be able to change resolution during rotation (you may add an
extra excape code and do the resolution change using ExtEscape) and
should allocate a video "ram" buffer big enough to hold the highest
resolution you need to support.
Applications may not handle the resolution change gracefully, so you
may have to modify them or implement some mechanism to resize their
window to force an update.

--
Valter Minute
www.fortechembeddedlabs.it
Training, support and development for Windows CE
(the reply address of this message is invalid)

JamesCool
Sun Mar 30 17:39:09 PDT 2008

Valter Minute wrote:
>> Hi,
>>
>[quoted text clipped - 12 lines]
>> Do you guys have any other ideas to implement the dynamic change
>> of display resolution?
>
>You may be able to support resolution change by rotating the display
>two times.
>You rotate the display 90 degrees and then rotate it back, changing
>the resolution in the process.
>Obviously you should change your driver to support this "trick" (it
>should be able to change resolution during rotation (you may add an
>extra excape code and do the resolution change using ExtEscape) and
>should allocate a video "ram" buffer big enough to hold the highest
>resolution you need to support.
>Applications may not handle the resolution change gracefully, so you
>may have to modify them or implement some mechanism to resize their
>window to force an update.
>

Thanks Valter Minute,

What you mean is to do some modification in the display driver (sa2video.cpp
function DynRotate)?
But if i rotate the screen 90 for the first time and rotate it back, it seem
will end up the original resoultion, or could you give some example?

Thanks...
JamesCool

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Valter
Mon Mar 31 00:53:33 PDT 2008

"JamesCool via PocketPCJunkies.com" <u42351@uwe> wrote in
news:81f41d3fcce8c@uwe:

[...]
> Thanks Valter Minute,
>
> What you mean is to do some modification in the display driver
> (sa2video.cpp function DynRotate)?
> But if i rotate the screen 90 for the first time and rotate it
> back, it seem will end up the original resoultion, or could you
> give some example?
>

That's the default behaviour.
For GPE-based drivers the SetRotation member of GPESurf accepts screen
widt and height as input and at this point you can change resolution.
You will need to change also m_nScreenWidthSave, m_nScreenHeightSave,
m_cbScanLineLength members of your GPE object to match those required
by the new res and make sure that the main surface allocated at
startup is big enough to hold the highest-resolution you can select.

This is a "hack", so I can't grant that it works on any driver and
without causing some application issues.
The PXA27X driver released inside the mainstone II BSP was not as
"Production Quality" as you can expect.. so changing it may be a bit
complex. Re-implementing usign the generic-VGA GPE-based driver and
moving only LCD-controller initialization code to it may made the
transition simpler.

--
Valter Minute
www.fortechembeddedlabs.it
Training, support and development for Windows CE
(the reply address of this message is invalid)

JamesCool
Mon Mar 31 01:15:55 PDT 2008

Hi Valter Minute,

Thanks a lot for your advice.
I will first try to modify the default display driver that come with the
Mainstoneii BSP to verify the concept..

Best regards,
JamesCool


Valter Minute wrote:
>[...]
>> Thanks Valter Minute,
>>
>[quoted text clipped - 3 lines]
>> back, it seem will end up the original resoultion, or could you
>> give some example?
>
>That's the default behaviour.
>For GPE-based drivers the SetRotation member of GPESurf accepts screen
>widt and height as input and at this point you can change resolution.
>You will need to change also m_nScreenWidthSave, m_nScreenHeightSave,
>m_cbScanLineLength members of your GPE object to match those required
>by the new res and make sure that the main surface allocated at
>startup is big enough to hold the highest-resolution you can select.
>
>This is a "hack", so I can't grant that it works on any driver and
>without causing some application issues.
>The PXA27X driver released inside the mainstone II BSP was not as
>"Production Quality" as you can expect.. so changing it may be a bit
>complex. Re-implementing usign the generic-VGA GPE-based driver and
>moving only LCD-controller initialization code to it may made the
>transition simpler.
>

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