Re: AREF bypass capacitance on ATMega2560?

From	Joerg <invalid@invalid.invalid>
Newsgroups	sci.electronics.design, comp.arch.embedded
Subject	Re: AREF bypass capacitance on ATMega2560?
Date	2013-09-07 16:56 -0700
Organization	Consultant
Message-ID	<b91sp9F6pktU1@mid.individual.net> (permalink)
References	(15 earlier) <l0g38d$9ad$1@dont-email.me> <b91lacF5bvnU1@mid.individual.net> <l0g86a$8mr$1@dont-email.me> <b91nv5F5t7nU1@mid.individual.net> <67c36$522baf5d$5f6173bc$18503@abuse.newsxs.nl>

Cross-posted to 2 groups.

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Stef wrote:
> In comp.arch.embedded,
> Joerg <invalid@invalid.invalid> wrote:
>> Nope. Not if it's in the worlds of medical or aerospace. There you have
>> a huge re-cert effort on your hands for changes. New layout? Back to the
>> end of the line.
> 
> That is not always true (at least for medical equipment, no experience
> with aerospace). If the change is minor enough, it may be enough to
> write a rationale that explains the change and how it does not impact
> the function of the equipment. If the notified body agrees with the
> rationale, only a limitied effort is required to re-cert.
> 

I really doubt they would agree if a code re-compilation was required to
make this work. With code and firmware they have become very careful
because there have been to many mishaps.

Most of the time the notified bodies or even the FDA do not care much
about the code, they care about your process. So then the onus is on the
company, and there mostly on the VP of Quality Control. He or she will
normally not take a re-compile lightly, or as something that can be
brushed under the carpet as "not too risky".

It is the same with some hardware. I went through a whole re-cert once
just because we had to switcher the manufacturer for one little transformer.

The bottomline is that in the unlikely but possible situation where
something bad happens you need to be prepared. Then there will be a
barrage of request for documents from the regression testing and all
that. Woe to those who then don't have them.

>> Sometimes changing is very time consuming. I recently learned that this
>> is even the case for alarm systems. "If we even add as much as one
>> capacitor for EMC we have to go through the whole insurer certification
>> process again".
> 
> Weird, I would expect a similar approach with a rationale or something
> would be enough. 
> 

There are many other markets with similar requirements. One of them is
railroad electronics, especially for countries like Germany.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Thread

AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-19 13:14 -0700
  Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-08-20 20:16 +0100
  Re: AREF bypass capacitance on ATMega2560? Vladimir Vassilevsky <nospam@nowhere.com> - 2013-08-21 14:47 -0500
    Re: AREF bypass capacitance on ATMega2560? Jim Stewart <jstewart@jkmicro.com> - 2013-08-21 13:18 -0700
    Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-21 16:38 -0700
      Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-08-21 21:30 -0500
        Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-22 10:51 -0700
          Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 16:26 -0400
            Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-06 13:33 -0700
              Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 17:12 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-06 16:10 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 23:59 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 08:10 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:03 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 10:59 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 14:54 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:39 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 16:44 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 14:48 -0700
                Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-09-07 17:10 -0500
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 15:34 -0700
                Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-08 00:57 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 16:56 -0700
                Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-09 17:07 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 10:19 -0700
                Re: AREF bypass capacitance on ATMega2560? Paul <paul@pcserviceselectronics.co.uk> - 2013-09-09 20:27 +0100
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 12:55 -0700
                Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-11 09:44 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:27 -0700
                Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-13 12:42 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 11:56 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:38 -0400
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 17:39 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:20 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 07:41 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-07 11:17 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:23 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:19 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:03 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 19:42 -0400
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-08 17:18 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-09 13:13 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 20:21 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-10 23:42 -0400
                Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-07 09:24 +0100
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 10:00 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-07 11:32 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:35 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:30 -0400
                Re: AREF bypass capacitance on ATMega2560? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2013-09-09 09:56 -0400
                Re: AREF bypass capacitance on ATMega2560? Robert Wessel <robertwessel2@yahoo.com> - 2013-09-12 11:50 -0500
                Re: AREF bypass capacitance on ATMega2560? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2013-09-12 15:06 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 14:57 +0200
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 00:21 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 14:08 +0200
                Re: AREF bypass capacitance on ATMega2560? Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-09-13 15:15 +0100
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 11:46 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 18:43 +0200
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 19:14 +0200
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 15:26 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 15:24 -0400
                Re: AREF bypass capacitance on ATMega2560? David Brown <david.brown@removethis.hesbynett.no> - 2013-09-13 20:22 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 09:32 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:44 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:46 -0700
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 13:33 -0700
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 13:46 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 17:05 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 15:23 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:02 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 16:45 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:16 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 08:05 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:27 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 12:56 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:07 -0400
                Re: AREF bypass capacitance on ATMega2560? Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-09-11 10:05 +0100
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:49 -0700
                Re: AREF bypass capacitance on ATMega2560? Paul <paul@pcserviceselectronics.co.uk> - 2013-09-11 16:54 +0100
                Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-09-11 11:25 -0500
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 09:49 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:40 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:38 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 09:34 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:29 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 13:01 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:22 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:09 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:15 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 14:20 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 18:15 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 15:57 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 19:46 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 17:15 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 20:20 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 07:17 -0700
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 12:17 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-09 19:30 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 16:38 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-10 14:02 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:41 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-11 00:04 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:53 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-11 21:50 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 09:58 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-12 18:54 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 16:17 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 10:03 -0700
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 19:24 +0200
                Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 20:38 +0300
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 11:23 -0700
                Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 22:36 +0300
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 12:41 -0700
                Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 23:08 +0300
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 11:19 -0700
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-12 18:59 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 13:00 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 12:05 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-12 16:03 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 14:42 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 00:24 -0400
                Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 14:27 +0200
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 12:07 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-15 02:26 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-15 09:51 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-13 20:06 -0400
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 16:50 -0400
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 14:33 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:07 -0400
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 16:31 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:38 -0400
                Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-08 20:19 -0700
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:36 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:46 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:36 -0400
                Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-08 09:04 +0100
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 13:42 -0400
                Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-08 19:04 +0100
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 07:29 -0400
                Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-09 08:56 +0100
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:54 -0400
                Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:24 -0400
                Re: AREF bypass capacitance on ATMega2560? Ulf Samuelsson <ulf_samuelsson@invalid.telia.com> - 2013-09-07 20:11 +0200
                Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 15:06 -0400
                Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:54 -0700
    Re: AREF bypass capacitance on ATMega2560? Ulf Samuelsson <ulf_samuelsson@invalid.telia.com> - 2013-09-02 22:27 +0200

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