I am pretty new to this stuff, but I am usually able to work out problems on my own. I am trying to interface to some humidity sensor that uses it's own proprietary 2-wire serial interface (clock line and a data line). To make things easier, I declared sbits for each pin (SCK and DATA). When I try to compile and execute code like this: . . DATA = 1; SCK = 1; error = DATA; SCK = 0; . . the compiler omits the line "SCK = 1". This is just an example, and it happens sporadically throughout the code. I read on some other posts that sbits are automatically volatile, and similar rumors, but the compiler is optimizing necessary lines out anyway. My compiler version is 6.20a. Thanks