AVR-Chat

--- In AVR-Chat@yahoogroups.com, "Tim Mitchell" <tim@...> wrote:
> Also if you have another AVR board with external crystal on you
> can run that up and connect one of the XTAL pins on it to
> drive your defunct board.
I believe that that tactic will work only if the operational AVR board is configured for a full-swing oscillator.  If it isn't, you can always write a quick program to toggle an output pin or generate a signal using a timer.  Also, some AVRs have a "CLKOUT" signal which will make available a full-swing clock signal on an I/O pin.

There are a lot of options for a usable external clock signal.  The venerable 555 timer can be used to generate a clock signal, for example.

Depending on the frequency of the external signal that you use, you may have to re-configure your programmer to run at at a lower frequency.  I think the general rule for ISP programming is that the ISP clock must be no more than 1/4 of the operating frequency of the device being programmed.

Don Kinzer
ZBasic Microcontrollers
http://www.zbasic.net