Hi Roy, > I should know the answer :-( > But when I declare a constant > Test equ 5 > MPSIM shows the constant Test at address 5. > How do you get MPLAB to assign a constant a value that can be used in > calculations? It is only a problem with MPSIM. The generated code must be ok. As you can declare a constant and use this value to address some registers, the simulator will see this value as a register :(. Take a look at the generated .lst file to check if the preprocessor has done his work. The equ directive is the good one to declare constant. Best Regards, Nicolas -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist