>Unfortunately, the page boundry on a 16C73 is at 07FFh. >My code only goes to 012Dh. >The lookup table is only 256 values. >I was so hopefull! You just described the problem! Pages (I call them 'segments') in the '73 are only 256 bytes. I'll bet you find that your table crosses a page boundary such as 0x100 or 0x200. I do think that is your problem. dwayne Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 15 years of Engineering Innovation (1984 - 1999) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. My posting messages to Usenet neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.