1.8" TFT LCD with black tab - swapped colors

[Andy_123]

I am not sure if this is dispaly related or not:

What I see is if I dispaly 8 basic colors then
RED/Blue collors swapped
Yellow/Cyan swapped

Green, Magenta, Black and White are OK
If I remap codes in .h file then display shows basic colors correctly

Yellow is a combination of Red and Green
Cyan is combination of Blue and Green

It feels like Blue and Red pixels are swapped... Is it even possible?

I tried multiple examples - all giving me the same result.
Any Ideas?

Thanks

[Andy_123]

I have suspision that hardware pin SRGB of ST7735 on my display is not set correctly

To invert it, I was able to clear RGB bit it in MADCTL register (ST7735.cpp file) and now it looks correct.

Any other ideas?

[adafruit_support_rick]

We stock 3 different 1.8" TFT devices. What is the product ID of the screen you have?

[Andy_123]

I just want to bring this thread back - it appears that black tab displays have RED and BLUE colors swapped and library was updated recently to address this.

It was done by swapping BLUE and RED colors before sending each pixel - from my tests that slows down dispaly dramatically

Code: Select all

if (tabcolor == INITR_BLACKTAB)   color = swapcolor(color);

Also "if" check performed at runtime that takes extra time - if should be done at compiler level I guess.

The more efficient way is to clear RGB bit in then MADCTL register - this will automatically swap colors and no swapcolor() is necessary.

Here are simple changes:

Replace 0xC8 witt 0xC0:

Code: Select all

    ST7735_MADCTL , 1      ,  // 14: Memory access control (directions), 1 arg:
      0xC0,                   //     row addr/col addr, bottom to top refresh


Also remove all instances of MADCTL_RGB from setRotation

[adafruit]

Thats right! thanks for the reminder, latest github library has this fix and supports all tab colors