The C# application I'm working on needs to be able to be able to call a function within 5 milliseconds of a digital input signal's state change (0V = off, 5V = on).
Rather than using software to repeatedly poll that input's state, I would like some hardware to simply call a software function when the hardware detects a state change (like how hardware interrupts work).
Does anyone know how to do this (what ports to use) on a standard PC tower? Or does anyone know of any hardware peripherals that allow this functionality?
Occasional latencies are fine. I need <5ms average.
I basically need to take as many samples as possible of the input digital waveform. (preferably in the C# program, rather than in a peripheral micro-controller, although I am open to suggestions).
For instance, I found out the Labjack U3 can poll its digital input in less than a millisecond. This is a valid answer to the question, but I am interesting in more answers, especially ones that don't use polling or poll faster than 1ms.
High input impedance would be nice (digital inputs).