Hi Mr (probably not so) Smiley (at the moment) On the face of it, the stack seems accounted for Two things I could suggest - 1) adding NOPs between I/O, just in case it happens to be a read-modify-write problem 2) checking that the DIG_BMP section is not, for example, straddling a PCL boundary Joe --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .