Does anybody know what is the shortest pulse width that the Raspberry Pi (any model) GPIO interrupt pins can detect? I have a project in mind, but the pulses would be between 5 & 17ns wide.
The GPIO peripheral is identical on all Pi models. The only difference is in the number of GPIO routed to the expansion header.
The Pi has a
GPIO Asynchronous rising/falling Edge Detect mode.
See pages 99/100 of BCM2835 ARM Peripherals.
"Asynchronous means the incoming signal is not sampled by the system clock. As such rising/falling edges of very short duration can be detected."
I'm fairly sure that 4ns will be detected.
I don't know if this mode is the Pi default. You will have to experiment.
As joan has said this should be possible. 5ns corresponds to 100MHz and should be within the Pi capabilities. Your problem will be delivering the signal. A terminated transmission line would be required.