I wonder if a simple 7555 timer would work? (the lower power and supposidly faster version of the 555). I looked for a "high speed" monostable but didn't find much.

As I understand it, the 7555 has no "clock", it's just an internal network of transistors and it would seem that if the circuit were "tripped" by anything, it would transition - I don't see any time spec on minimum trasnient duration required to cause a transition. Anyone have an idea on that?

If it were too short (say a fraction of a nanosecond), you'd think it would trip on its own from time to time just from radio spike hits and what not.

With everything on the planet running at multiples of gigahertz these days, I didn't think this would pose any real challenge but it is indeed complicating things.



BrianT - thanks man. I found the very same thing in my own data sheet. Didn't exactly make it perfectly clear did it. I got the same read - that the event must last long enough for the program to execute a read and register that the pin has indeed changed state.