Hi, thank you for your answers.
I downloaded the example from the link above and then compare my example.
Yes, I found few differences and then I remeber that I wrote some changes during finding the problem... last week.
As I mentioned in my posts above in this moment I am using a modified Adafruit RGBmatrix from this Topic: P10 32x16 LED panel 1/4 scan now works with Adafruit_GFX - LEDs and Multiplexing - Arduino Forum
With original library I do not have big success. When I try to write only a pixel, then I saw two pixels, and then they are shifted to the left instead to to right if I increase X value for position, then suddenly change the row position,...
With modified library I have 100% control for X position and partially for Y.
The problem is that Y instead 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 row goes: 5,6,7,8,1,2,3,4,13,14,15,16,9,10,11,12.
I see that on modified library one can connect more than one module so in the line:
RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, false); one additional parameter is added: RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, false,1); . The last paramater (1) determn, to show pixels on the first module.
I am studying this module one week and even first time I opened the library and try to find how this works. But the code in library is written more complicated as I am used from Arduino IDE. I've lost in the code.
From the original Adafruit tutorial: Connecting Using RGB Matrix Shield | 32x16 and 32x32 RGB LED Matrix | Adafruit Learning System
I can see now, that they are talking about two module types: 16x32 and 32x32. So I assume the library works only for this two types. I have no idea where and how to tell to software which module you have connect.
I will now follow the siggestion of TomGeorge and goes through all Library examples, maybe I will find something to solve my problem.
Now I am adding modified Adafruit RGBmatrix library.
RGBmatrixPanel.h (2.11 KB)
RGBmatrixPanel.cpp (27.2 KB)
gamma.h (1.51 KB)