This may be a trivial question.
I have a microcontroller that will attempt to recognize the rising and falling edges of a pulse. This pulse is not in sync with the microcontroller's clock or any clock. For my intents and purposes, the voltages are adjusted to the voltages that the microcontroller requires. How should I expect the microcontroller to behave if it tries to detect the rising edge when...
...the pulse begins near the beginning of the clock cycle?
...the pulse begins in the middle of the clock cycle?
...near the end of the clock cycle?
As well, what should I expect if I try to detect the falling edge with the same timings? (1. near the beginning, 2. in the middle, 3. near the end)
I don't know if this question depends on the specifics of the MCU or the pulse. If so, I can provide specs. Thanks!
EDIT: I think I worded my question poorly. I understand that the MCU will only sample each clock cycle. I was mostly asking what would happen if the pulse were to change polarity in the 1. beginning, 2. middle, 3. end of a clock cycle. Will this affect what the MCU samples?
Specs: ARM9 MCU http://www.nxp.com/documents/data_sheet/LPC3141_43.pdf
Pulse: Pulses are generated by an avalanche photodiode. Each pulse represents the arrival of one photon. Pulse high lasts 30 ns, pulse dead time is minimum 50 ns. The current goal of my project is to use the internal timer to time these pulse arrivals.