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Last Post 03 Nov 2004 10:34 AM by  ftiernan
VGA to QVGA Problem
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ftiernan
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02 Nov 2004 09:16 AM
    I have built a custom display based platform with a simple application using the logic LCD 6.4 VGA display and everything works fine. I want to modify this platform to work with the logic 3.5 QVGA display. I attach the 3.5 QVGA display and change the default display to 6 using logic loader video-set-default command and then test it using the draw-test command and it shows the correct "flag'" display. When I load my platform however the display is backlit but blank. Using the Remote Registry Editor I can see that HKEY_LOCAL_MACHINE\Drivers\LH7a400_LCD entry for DisplayNumber is set to 5 but changing it to 6 makes no difference and when I reload the platform it goes back to 5. Also rebuilding the platform doesn't seem to make any difference (i.e. screen blank and DisplayNumber set to 5). I'm sure it's something simple but for now I'm stuck. Any suggestions...? thanks

    Frank
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    02 Nov 2004 10:26 AM
    ftiernan,

    When you say you rebuild the platform do you do a 'clean' first then hit build? In what file are you specifying the display that you want to use? Is it in the .reg file of the driver? In addition to that I'd be interested in seeing the procedure that you're using to load your image, i.e bootstrings that you're sending and the like.

    Regards,
    mikea@logicpd.com
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    02 Nov 2004 04:49 PM
    ftiernan,
    When you change the registry using the Remote Registry Editor, I'm guessing you are not using a 'hive' registry. That means any changes you make are lost when you do a power down, since they are just in RAM. If you want more info about the hive registry, check out our white paper on it use or the CE help.

    In order to use display mode 6, in the driver, you are correct in that you must change the registry number. You can find this in the driver's .reg file. You must change the 'DisplayNumber' key to 6. The default is 5. Please be sure that when you change this and build you check your reginit.ini file to be sure you changes were copied into the release folder. This file is located in your project's release folder, in the Public folder (WinCE 4.2).

    There is one other option you can use. When you provide the boot string when jumping to CE from LogicLoader, you can use the 'disp_num:6' boot string to over-write the value built into the image's registry.

    Both of these items our documented in the driver's .reg file and release notes if you need more information. Information about boot strings can be found in the LoCE BSP user notes which should be provided with the latest OAL release.

    Hope this helps,
    -Mike A.
    ftiernan
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    03 Nov 2004 10:34 AM
    MIke and Aaron,

    Thanks for the help. As you suggested, when I directly edited 'DisplayNumber' in driver .reg the problem was solved!

    My original confusion came from the fact that the driver .reg file was not shown in the Preferences section of the Workspace window in PB4.2. But your replies pointed me in the right direction. Thanks again for the quick assistance.

    Frank T.
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