AVR-Chat

Now, do you usually need to remove the chip to reprogram?

So the fuses are "soft" fuses and can be reset huh?

Okay so basically the SPI interface (and yes, I knew about the alternate
pins) is good to use, just make sure to NEVER blow the wrong fuse when
programming.

Normally I don't think I would even need to change the status of a fuse
in the field.

Barry



-----Original Message-----
From: Brian Dean [mailto:bsd@bdmicro.com] 
Sent: Sunday, March 28, 2004 1:01 PM
Subject: Re: [AVR-Chat] Re: start AVR

On Sun, Mar 28, 2004 at 12:27:40PM -0800, LightYearCS wrote:

> Oh!  Of course.  That kinda went without saying I thought.  So, you
> basically need the clock whether it's internal, external crystal, or
> external clock and it must be running.  Gotcha :)

Right.  A common error is to solder on an external crystal, and then
configure the fuse bits for an external clock.  Crystal != clock.
When that happens, the only way to regain programming mode (assuming
ISP) is to input a clock signal, perhaps desoldering the crystal in
the process, re-enter programming mode, and reset the fuses.

It's just something to be aware of - no need to dwell on it.  But
usually when one has previously had the chip running, then made some
fuse bit changes perhaps to enable some unrelated feature, and the
chip no longer appears to work, this is the problem.

-Brian
-- 
Brian Dean
http://www.bdmicro.com/

 
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