Yes I have seen this trouble. In a noisy system, if MCLR dips below it's trigger point even for a few nanosecs, the PIC can do funny things. One of the most common symptoms is partial reset. The PIC does not reset it's program counter, but will run really, really slow or do other crazy things. Scoping the MCLR pin with a fast scope revealed the problem. I ended up with a capacitor on MCLR that seemed inordinately large considering there was a 10K to 5V. Also I had to reroute the trace because the original trace was long, making it into an effective antenna. -- Lawrence Lile Senior Project Engineer Toastmaster, Inc. Division of Salton, Inc. 573-446-5661 voice 573-446-5676 fax Josh Koffman Sent by: pic microcontroller discussion list 12/10/2003 10:31 AM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: Re: MCLR pin problems Are you sure it's resetting because of an MCLR reset? Could it be a brownout reset, or something like that? How do you know the chip is resetting at all? Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams Tuprul G\GL\ wrote: > I'm having some problesm with 18F458 ,First I thought it is because of PIC C > compiler's float library but then realised that it's not a software problem > .}t is because of unstable behaviour of MCLR pin. > Altough I pulled up that pin sometimes it resets. > Has anyone saw this touble before? -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.