From PICLIST@MITVMA.MIT.EDU Fri Nov 15 02:16:27 2002 Received: from cherry.ease.lsoft.com [209.119.0.109] by dpmail10.doteasy.com with ESMTP (SMTPD32-7.13) id A97B17B100D6; Fri, 15 Nov 2002 02:16:27 -0800 Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <23.007DB535@cherry.ease.lsoft.com>; Fri, 15 Nov 2002 5:02:24 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8d) with spool id 0415 for PICLIST@MITVMA.MIT.EDU; Fri, 15 Nov 2002 05:02:12 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 5756; Fri, 15 Nov 2002 05:00:17 -0500 Received: from nameserv.rl.ac.uk [130.246.135.129] by mitvma.mit.edu (IBM VM SMTP Level 320) via TCP with ESMTP ; Fri, 15 Nov 2002 05:00:16 EST X-Comment: mitvma.mit.edu: Mail was sent by nameserv.rl.ac.uk Received: from sstdwkiwi (sstdwkiwi.ag.rl.ac.uk [130.246.189.231]) by nameserv.rl.ac.uk (8.8.8/8.8.8) with SMTP id KAA26832 for ; Fri, 15 Nov 2002 10:00:16 GMT References: <001501c28c38$4f5c4720$0a01a8c0@djm> X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4807.1700 X-MIMEOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 Message-ID: <00f901c28c8d$cc6b59e0$e7bdf682@sstdwkiwi> Date: Fri, 15 Nov 2002 10:00:16 -0000 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: "Alan B. Pearce" Subject: Re: [PIC]:failed data location? To: PICLIST@MITVMA.MIT.EDU X-RCPT-TO: Status: R X-UIDL: 277600619 X-Evolution-Source: pop://mailinglist%40farcite.net@mail.farcite.net/ Mime-Version: 1.0 X-Evolution: 00000743-0000 >As I've said, I replaced the chip & thinks are OK - for >now. But what's to prevent a failure down the road? Nothing. You have just restarted the MTBF clock at zero time :) You are now looking at the reason why safety critical items are required to do a power up functionality test of the processor, as has been discussed on this list a number of times. There is one way to get around the problem. Multiple processors, with majority voting to determine who is correct/failed. Use multiple flags within your software, again majority voting between them to determine the same thing. whatever, you end up with more code that could go wrong :) -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.