I am not sure this is the right place to ask this question, but did not see any communities dedicated to Atmel chips.
I used a scope to look at my atmega328 clock signal (pin 14) and got the following result.
I expected a square wave, not a notched sine wave, but I have no basis for that expectation. So, is this what the signal should look like, or do I have some problems with my clock setup (noise, wrong caps, etc). I am using a 16MHz crystal with 22pF caps to ground wired to XTAL1/2 (9 and 10). The clock frequency looks dead-on at 16MHz, 62.3ns which you can see on the scope. Supply voltage is coming from a 7805 (fed from a 12V wall wart) Does this indicate a noise problem (need additional capacitors perhaps) or maybe this is actually what the signal looks like?
Second question this made me think of, what generates the clock signal anyway? (If I need to ask that as a separate question I will).
The probe is a 10x probe, 100 MHz. It was not calibrated when I measured the above signal, so I calibrated it per Stratton's instruction. The probe is now compensated as can be seen here (820 microsec period = approx. 1.22kHz which is what it should be)
Now when I hook everything up, I get the following, it looks worse...
Could the notching be strictly from no bypass capacitor at the chip? I find that hard to believe, but I have never done this experiment, so I am out of my league!! I know every thing I have read and learned says to use them, it would just be amazing.
Also, I included a picture of the setup just for clarification. Maybe you can see something you don't like (besides my poor ability to build a test board!!)