Calling all AVR wizards! (I need some more help!) Updated! Answered
New stuff's in bold
I'm trying to build a clock-type-thing for my research project this year, and I need some help.
First, I need to know how I can run my ATtiny2313 off of a 12mhz external clock. No, not crystal, external clock. (this holds true)
Second, I need to know how to use interrupts (in general) to program a clock. I really just need some bare code or help, and any help is greatly appreciated.
So, I figured out how to use interrupts, and it's pretty simple, actually - I'm just having one small problem - why can't I write to global variables in an interrupt service routine (ISR)? Any clues on how I can talk back to the main routine from an interrupt?
Picture courtesy of Oskay!