Jan, the method Ian suggested is not a 'hack' - it is a very common way of doing it. The downside with Ian's method is that you have to be sure of what is connected to those port pins as you are doing a read-modify-write. If the logic levels are not correct on those port pins due to loading they will not read correctly and when you write them back you'll have problems. If you know you have light loading of those port pins you can be reasonably sure Ian's code will work as expected. This is a trap for the unwary! Generally I don't do read-modify-write on ports because of this, it is always safer to keep a copy of the port states in a variable and modify this variable then copy to the port.