I'm having a strange problem with the ADC on a Mega168. I'm using it in a fairly high power voltage converter for one of my high voltage projects. I've made dozens of these without any trouble, but this one is a bit higher powered than the rest. Anyway, the problem is the ADC interrupt stops. Everything runs nicely until suddenly there are no more ADC interrupts and the converter just sticks at whatever value it happens to be. I don't know whether it's because it aborts the conversion, or because the int enable bit or the int flag itself gets reset, or maybe the entire ADC subsystem gets reset. This only happens during load shedding, when it switches from a large load (3A peak current) to a light load (1A or less). Obviously when that happens there's some overshoot from the energy stored in the inductor, so I'm hoping it's just a noise problem that will go away if I make another prototype. I'll try emulating it with DebugWire when I have time and hopefully find out exactly what's going on, but meantime I throw it out here in case anyone else has seen this and has some advice.
Edit: correction: I'm running it on a Mega48 at present, not a 168.