Sometimes one of the functions F1...F4 doesn't change when pressing the button on the 6021

[Erwin007]

Sometimes one of the f1 ; f2 ; f3 or f4 doesn't change when pressing the button on the control unit 6021. It is not allways the same function button that doesn't react anymore. I can't give steps which you have to do to let one function be blocked. If it occurs that a function is blocked you can solve the problem by changing the speed. What is here the problem? Is it a problem on the 6021 or is it a problem with the arduino code? I even changed your code in another one where I've got the same problem. You find my code with this message. MyMaerklin program.txt