Building an axis and button box

[Jack_Aubrey]

As i like to fly the really big planes, i'm building a new controller from an Arduino Uno (it still has a long way to go) but recently i realised that i dont know how many axis, buttons and hats per controller admit the Il2... I thought it would be as directinput (8 axis, 128 buttons and a hat) but i found out that this could be wrong.
So anyone knows how many axis, buttons and hats per controller admit the il2??????????