[Qt-embedded-interest] Qtopia2.2.0 on MPC5121

[Shen Li-R64465]

Hi, Alex
I think we have found the root cause of the MPC5121 board issue. It is due to the ADS board wrongly connect the DDR MVTT and MVREF signal together. Normally this two signal should be separately supplied 0.9V . When transfer large white color, the Data bus will stay high voltage in a long time , and drag lots of current from MVTT, which will cause the +0.9v_CPU drop down, as the MVREF is very sensitive for the voltage, that will cause the DDR module logic error. 

 

After we separate the 0.9v supply for MVTT and MVREF. The issue is solved. And now the system can stable display white color even in full screen.

 
B.R
ShenLi




-----Original Message-----
From: qt-embedded-interest-bounces at trolltech.com [mailto:qt-embedded-interest-bounces at trolltech.com] On Behalf Of Alex Cucos
Sent: 2009年7月10日 linPM19:12
To: qt-embedded-interest at trolltech.com
Subject: Re: [Qt-embedded-interest] Qtopia2.2.0 on MPC5121


> Date: Fri, 10 Jul 2009 09:43:40 +0800
> From: "Shen Li-R64465" <Li.Shen at freescale.com>
> Subject: [Qt-embedded-interest] Qtopia2.2.0 on MPC5121e
> To: <qt-embedded-interest at trolltech.com>

> Hi,
> I have ported qtopia2.2.0 on MPC5121e. Now when I set the LCD
> resolution as lower than 640x480, the qtopia can run smoothly.
> But if I use 800x600 or 1024x768, the system will crash(the console
> output nothing, just frozen even if I enabled kernel debug info) . I
> am sure that I have provide enough frame buffer size as I configed it
> as 15MBytes. My kernel version is 2.6.24. Does this kernel has
> limitation on supporting qtopia2.2.0 resolution?
> 
> Is there any idea about it?Thanks!
> 
> B.R
> ShenLi

Hi ShenLi,

I have crossed compiled Qt Embedded 4.5.0 for the MPC5121e board and experienced similar system crashes. They were happening after an image containing lots of white pixels (e.g. maximized QTextEdit widget) was written to the frame-buffer.

It seems to be a hardware problem and has nothing to do with Qt, I reproduced the crash from outside Qt by writing white pixels directly into the frame-buffer.

A temporary fix was to customize the Qt widgets, replacing the white background with a different color (e.g. light grey).

Best regards,
Alex.

--
Alex Cucos
Senior Embedded Software Engineer
Blue Tree Systems
1, Galway Business Park
Dangan
Galway
Ireland
t: +353 91 520053
f: +353 91 520622
e: alex at bluetree.ie
w: http://www.bluetree.ie


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