Also, do you think the delay will be consistent on each iteration? Even if it's 5 microseconds, I can deal with it if it's always the same.
if the timer ISR is active the user interrupt has to wait for the timer interrupt ISR to finish
so consisten latency is kind of important.
Quoteif the timer ISR is active the user interrupt has to wait for the timer interrupt ISR to finishSince I call a single iteration of Timer1 in this interrupt, I know that Timer1 won't be busy. As far as Timer0 goes, I don't think I would have any code beyond the Ethernet polling that would be operating that would use it.I don't know anything about Ethernet, but the arduino start-up default sketch coding will activate timer0 unless you take explicit steps to disable timer0 interrupts, and as I said disabling timer0 will break certain arduino functions you might be using. My application is film scanning. The delay between the incoming pulse on INT0 affects the vertical framing of each frame, so consisten latency is kind of important.