Hi there The difference I remember is the fuse bits are backwards - If you are programming a F series with a 'C' programmer, invert the WDT bit (SET = WDT off) and vice versa. No other things have changed Richard P -----Original Message----- From: enpassant [SMTP:enpassant@AMERITECH.NET] Sent: Saturday, November 28, 1998 7:03 AM To: PICLIST@MITVMA.MIT.EDU Subject: 16C84 vs. 16F84 As I understand it the 16C84 and 16F84 are essentially the same chip, but I have not had much success using 16C84 code directly on a 16F84. Can someone please answer the following questions.. 1) What are the differences? 2) Can a program written for 16C84 be used *EXACTLY* as is for the 16F84, including assembler instructions and memory address references? 3) If answer to #2 is *NO* what modifications are necessary. THANKS! -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Confucius says Support bacteria - it is the only culture some people have! <>< ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~