I haven't double checked my facts against the instruction reference, but I think you should perform a "movf I2C_TRANS_REG,w" after your iorwf to get the result of the ior into w for the first comparison. I think that iorwf with a destination of 'f' leaves 'w' unchanged - but I could be wrong. ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender. This footnote also confirms that this email message has been swept by MAILsweeper for the presence of computer viruses. ********************************************************************** -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body