While 805x's are similar in most respects, they don't all reset properly from the same circuit, at least not from the same RC circuit.

I've had it happen time and again, that a different time constant makes some of them reset while others won't. It seems to me, just from limited experience, and I've never used a "reset generator" for a number of reasons, though I have tried them out, that the nearer your reset pulse is to the shortest tolerable pulse for the MCU in question, the more different pin-compatibles will reset in that circuit. Of course, none of this applies to ATMEL parts, as I avoid them. I do have the best results with the Maxim/Dallas 89C4x0 series, as they have built-in circuitry to process the reset. They tolerate long or short pulses, slow rise and fall times, etc. I've found, however, that .1 microfarad with a 1K-ohm pulldown works fairly well with most, but not necessarily all, 805x types.

RE