locked out of Atmega

Development Boards MicroMod
1

so, here is a fun story.

the other day I purchased an VAR stamp. they seem pretty cool for rapid prototyping check it out:

http://www.futurlec.com/ET-AVR_Stamp_Technical.shtml

anyway, it runs at 16 MHz. I needed it to run at 8 MHz.so I changed the fuse bit to 8 MHz.

and that was all she wrote. I can no longer access the chip. what fun!!!

anyway, I was using a ISP to communicate with the IC. it would be a shame to throw the thing away just because of a clock divider fuse bit.

so here’s the thing,does anyone know if it would be possible for me to access the AVR through the Jtag interface and then correct the problem?

I hope so, but then again,…I didn’t think changing the clock speed would cause a lockout.

thanks a lot people.

J

2

the fuse bits select internal clock vs external crystal.

If you have the fuse bits set to external, then the frequency is determined by the crystal.

You may have change to internal clock or some such.

3

yeah, its just accessing the fuse bits thats now a problem. I bought a Jtag interface, so, maybe I will be able to communicate to the ic with that and then change the fuse bit back.

thanks.

J