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[avr-gcc-list] Re: optimizer removes volatile pin access code. why?

From: Joerg Desch
Subject: [avr-gcc-list] Re: optimizer removes volatile pin access code. why?
Date: Wed, 28 Oct 2009 12:44:48 +0100

Hi David,

On Wed, 28 Oct 2009 11:02:35 +0100
David Brown <address@hidden> wrote:

> Joerg Desch wrote:

> Have you checked things like the direction setting for the pin, or if
> it is used by a peripheral?  That might sound obvious, but sometimes
> the little things get forgotten.

Yes, I know. But all this is working fine. Using -Os had solved the

> The normal practice is to paste the snippet into the text of the email. 

Without the Makefile is would be a snippet. ;-)

For now I have the problem, that I can't reproduce the code which leads
to the missing code. I've worked on the project after posting here. The
code snippet I had extracted this morning doesn't show the problem too.

So I have to play with it in order to get the same effects.

I've talked to an colleague this morning. He had the same problems with
WinAVR a few months ago. His solution was adding a asm volatile("nop")
between cbi() and sbi(). He had to generate a bus timing by software.

At the end, I don't have a snippet. But I'm trying to reproduce the effect.

Email: Joerg Desch <jd DOT vvd AT web DOT de>

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