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Colours inverted on AM335x

yoko19298
Intellectual 395 points

Hello friends,

I managed to bring up a LCD with AM335x but one problem persist and I'm running out of ideas :)

The test bitmap displayed on LCD has negated colours (all of them). R = 0 instead of 255 and so on.

I used bmpToRaster to generate the image.h (btw. when used in 565 mode and COMPRESS is active -> segmentation fault). However, I generated a 24 bit RGB uncompressed image which is displayed well.

But all colours are negated, like in any image editing program I use "Inverse" transform.
The pins of LCD are correctly connected.

I tried with RasterMSBDataOrderSelect() and RasterNibbleModeEnable() but no effect.

Any idea please ?

  • 0
    Intellectual 395 points

    Solved :) There was nothing wrong with AM335x :) except errata and indeed, RED color is swapped with BLUE at SoC pins when using full 8-8-8 mode.

    My (unknown brand) 4.3" LCD labeled RD35004, expects some initialization data through SPI or I2C interface. For the moment, I left connected that interface to old MPU and now, works like a charm. I suspect some factory adjustments goes to that interface @rest since now all params are quite changed too ( V, H porch, length, etc).

    These days probably I'll see the hole burst and try to implement too in u-boot. So this was the mysterious "inverted color" issue.

    Best regards,

  • 0 in reply to yoko19298
    TI__Guru**** 393215 points

    Thanks for updating the thread with your solution.

  • 0 in reply to yoko19298
    Prodigy 120 points
    Hi yoko,
    I got the same problem. Here we have a custom board based on am335x sk with a 10.1" LCD. When staring kernel, the logo is quite "blue", but after that, the color of QT seems quite normal. Would you please tell me how to solve this problem in detail because I'm new about it?