# One step forward, one step back

**URL:** <https://community.sparkfun.com/t/one-step-forward-one-step-back/5143>\
**Category:** MicroMod\
**Tags:** avr-atmel\
**Created:** [August 25, 2007, 2:52am UTC](https://community.sparkfun.com/t/one-step-forward-one-step-back/5143 "2007-08-25T02:52:06Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![OldGrover](https://avatars.discourse-cdn.com/v4/letter/o/b782af/32.png) [@OldGrover](https://community.sparkfun.com/u/OldGrover)\
**Post date:** [August 25, 2007, 2:52am UTC](https://community.sparkfun.com/t/one-step-forward-one-step-back/5143/1 "2007-08-25T02:52:06Z")

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Heh. Well, got a little further, but seem to have dug myself in a deeper hole. Got to the point where I wanted to hook up a 16mhz crystal to the atmega168, so my pretty light would blink faster. To do that, of course, I needed to set fusebits… and I guess I set them wrong.

The fuse bytes the ic came set with were :

default lfuse : 0x62 01100010

default hfuse : 0xdf 11011111

I thought that for a 16mhz crystal, I needed to set CKSEL3…1 to 111 - but now I suspect that’s wrong - I think I wanted ‘full swing crystal oscillator’ - so 011… and thus I needed to set cksel0 and sut1…0 as well. I think what I want for lfuse is : 01110111

Damn.

In any case, I set the lfuse wrong and :

1. I can no longer talk to the darn thing, so I suspect I am toast. Any way to get it back talking to me - assuming I have no other ICs or anything at all interesting? I am using the stk200 from Sparkfun

2. Is the above what I actually wanted?