Hi All, Check if the 84 has an A after the number. We are also having problems with the A which is a die shrink. All our 12c509 software does not work properly on a 12c509a. Comments Julian Fine Eagle Wireless Security http://www.eagle-wireless.co.za -----Original Message----- From: Tony Nixon To: PICLIST@MITVMA.MIT.EDU Date: 09 April 1999 12:38 Subject: Re: New date code pic16F84s not programming I've noticed this myself with some newer 16F84's. I wonder if the programming specs have changed a little. Regards Tony