Hey All,

I'm trying to figure out how much in time the internal 8Mhz clock drifts in an hour in the Atmega328p. I've read that it is +/- 10% but I'm not sure how to do the calculation to get that into a measurement of time.

I'm just trying to compare it to an external 8Mhz clock for my current project and for future reference so I can easily figure out if I need one or not depending on the time sensitivity.

If you could layout the math for me I'd appreciate it. I like to learn to fish.