Hi Ken, Thanks a lot for your reply. >CLRW is a 14-bit core architecture-specific instruction mnemonic. >It is not a legal PIC18 architecture instruction mnemonic. Ain't the 14-bit core is a subset of 16-bit? Regards, WH Tan -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu