I'm working on firmware for LED display composed of Chinese RGB LED matrix modules (1/4 scan, 16x16, RGB). I want to find out how some pictures are displayed in three colors, is there any idea behind this, I know we're using different duty cycles (PWM) for different brightness of pixels but how all that is combined and well displayed on that big display panels? Is this control very complex or it just seems complex to me?

I'll be very thankful if anyone explain this or have an idea from where to start when writing firmware for displaying full color images on RGB matrices?


1 Answer 1


Based on what you write, it's hard to know any specifics, but let' discuss the basics.

if you have three LEDs, red green and blue, and maximum brightness of all of them is calibrated, so all three will look as white, then you can encode any color using different RGB values. Well, roughly any color- in professional equipment you have those color profiles, etc., which both combine the brightness calibration and define the color space.

Now, if you are going to show somehting on the matrix, you are expected to have an array of pixels, each will have a value of R, G and B, and you will have to find a way to "download" it once in a while to the matrix. If the display has a controller, i believe it will do the scanning, you just have to update it.

  • \$\begingroup\$ If I think right I need to have PWM values for every single pixel (RGB) on display depending on content i need to display stored in 3 different arrays \$\endgroup\$
    – user76920
    Commented May 22, 2015 at 11:34
  • \$\begingroup\$ That's one way. Actually, bmp files are such arrays. Except some header, their structure is like that:R, G, B, R, G, B, R, G, B... each R G or B are a byte (or less, if it's not 24bit bitmap) \$\endgroup\$
    – user76844
    Commented May 22, 2015 at 11:44
  • \$\begingroup\$ What display have you got? \$\endgroup\$
    – user76844
    Commented May 22, 2015 at 11:45
  • \$\begingroup\$ P10-RGB-16x16 module, but working principle is not so important as how to display full color images on rgb matrices, I'm already working on adapting the content to matrices. \$\endgroup\$
    – user76920
    Commented May 22, 2015 at 11:47
  • \$\begingroup\$ Good luck. Be sure it actually has brightness controls, maybe it's just on/off for each led. also find display's datasheet, usually it's useful \$\endgroup\$
    – user76844
    Commented May 22, 2015 at 13:18

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