Hello,
I'm designing a servo controller based on the 328P microcontroller. Problem is, when I connect this circuit to battery power instead of my signals I detect mains noise at 60Hz on every pin of the microcontroller, at an amplitude of about 2V, which seems unusuaully high to me. The only pin showing any kind of different behavior is the oscillator in pin, which shows the oscillator 20MHz signal riding on top of the larger and slower noise signal. The battery in open source configuration does not show such a huge mains component.
I also tried connecting to a variable power supply unit I have (ebay stuff), but its output on the oscilloscope shows some giant blips (peak to peak of up to 10 volts) so I'm not sure I should be using that to power my MCU.
I've attached a pdf of the circuit, please let me know if you need more info. Thank you.