Micros() again

I have my ballistic chrono working and wasn't satisfied with the 4us resolution of the micros() function. So I converted it to a parallax propeller with 12.5ns counter resolution. Then I started thinking that maybe there is a counter that has higher resolution if programmed in assembly on the arduino? I looked around, downloaded the datasheets and couldn't find an answer. So if I convert to assembly on the arduino is there an equivalent (to the propeller) system clock counter that would give me higher than 1 / 80,000,000 or 12.5ns res? I don't want to start a timer on the chip as much as just read it twice. Also, the timer would need to be 32bits if running sub micro.

The slew rate on the optical detectors are 50ns 0 to 5v so I would like to match that on the arduino at a minimum. So I need an improvement in the arduino of a actor of 80 over 4us. Since the chrono uses three screens each 1ft apart, for higher accuracy we can use screens 1 to 3 or average of 1 to 2 and 2 to q3.

I am trying to stick with the arduino for a number of reasons.

Jerry

As the Arduino has a clock rate of 16MHz, with a fastest count rate of 8MHz, and only a 16bit timer, then none of the specifications you have asked for can be met without using a seperate IC for timing.

The fastest you can get is 125ns per tick using a timer in normal mode, however as soon as you try and do anything with that (such as an interrupt, or other code) you will find you can’t get anywhere near that in any useful manor.

The fastest you can get is 125ns per tick using a timer in normal mode, however as soon as you try and do anything with that (such as an interrupt, or other code) you will find you can't get anywhere near that in any useful manor.

I'd like to correct slightly, 62.5 nanosec, and using input capture you can get close to pointed 62.5 nanosec w/o worry much of interruption in code etc, at least for 2 events , third one, again, would be a problem.
Still, less than 50 nsec. It's true for all 16 MHz boards , except new one -Leonardo.
I'm just starting with Leonardo myself (since yesterday), and it looks like there is a timer with high resolution 64 MHz (96 ?) capability, and for my projects I also very interested if someone can step in and update all of us on this feature.