AVR-Chat

A rank newbie has a question.  These "fuses" that you
mention, are they one-time programmable (like a real fuse)
or are they really something like an EEPROM cell that can be
set and cleared at will?

Erikc  - firewevr@airmail.net
///
"An Fhirinne in aghaidh an tSaoil."
"The Truth against the World."
        -- Bardic Motto


----- Original Message -----
From: "chris atwan" <chrisatwan2000@yahoo.com>
To: <AVR-Chat@yahoogroups.com>
Sent: Friday, April 16, 2004 14:48
Subject: Re: [AVR-Chat] Re: keypad and mega64


> Brian,
>
> I verified that the JTAGEN fuse is "1".  Any ideas??
>
> Chris Atwan
>
>
> Brian Dean <bsd@bdmicro.com> wrote:
> Hi Chris,
>
> On Fri, Apr 16, 2004 at 01:56:39AM -0000, chrisatwan2000
wrote:
>
> > I checked my fuses with AVR Studio and the following
fuses are set:
> >
> > BOOTSZ=11
> > BODLEVEL=1
> > CKSEL=1111 SUT=11
> >
> > Any ideas??
>
> The above fuses are in the low fuse byte.  You want to
look at the
> "high" fuse byte - the JTAGEN bit is bit number 6.
>
> In Atmel terminalogy, a fuse is "set" or "programmed" if
it is '0'.
> It is "unset" or "unprogrammed" if it is a "1".  However,
I think in
> AVR Studio, a check mark on the fuse setting sets it to a
"0", i.e.,
> programs the fuse.
>
> Look at the high fuse byte, specifically bit number 6.  If
it is a
> zero, then the JTAG debugging interface is enabled.  If it
is a one,
> then it is disabled.  It is enabled by default, so unless
you disabled
> it, it is most likely still enabled.  If it is enabled,
then that
> would most likely explain the problems with your program
not getting
> the expected results when using PORTF.
>
> For more info, the "Memory Programming" section of the
ATmega128
> datasheet.  The high fuse byte is described on page 292 in
the version
> I have.
>
> -Brian
> --
> Brian Dean
> http://www.bdmicro.com/
>
>
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