AVR-Chat

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/