Re: [avr-libc-dev] Re: [RFC] Unified ELF file

[Michael Hennebry]

On Wed, 26 Sep 2007, Dave Hylands wrote:

> On 9/26/07, Colin O'Flynn <address@hidden> wrote:
> > Hi,
> >
> > > I propose a counter-argument: it makes no sense for *the user* to want to
> > > program a single fuse byte.
> >
> > I agree with Eric 100% here. If you are going to be setting the fuse bytes, 
> > you
> > *must* set them all. Otherwise you are assuming the current state of fuse
> > bytes. Sure they *should* be default, but if someone else had their hands on
> > the chip it might change. That's the sorta scenario where two months down 
> > the
> > road stuff stops working, and you can't figure out why...
>
> Perhaps, what should be included is a set of fuse bytes and a
> corresponding mask. This would allow the program to set just the bits
> it was interested in, rather than being required to set all of the
> bits.

He might not do it because it allows
something he wants to forbid.

How about eliminating the surprise issue this way:
Include the masks in the elf file.
Declare that a well-made tool will not accept a mask
other than all-ones unless explicitly told to.
A bondage and discipline tool will not
accept a mask other than all-ones.

Whatever is done, don't use default fuse values.
Default fuse values will produce surprises.

-- 
Mike   address@hidden
"Horse guts never lie."  -- Cherek Bear-Shoulders