Charles, you have obviously had very little experience with these 89C series parts. If you ever had, you would appreciate why Mike, Erik Andy, Jez and I all recommend reset generators, especially in a noisy environment, but more pratically because it represents good practice, and will help cover our arses if something ever goes wrong with a critical system

I would like to join the group of people prefering to use a reset controller. Charles, you aren't right! And you never read those erratas, where the use of reset controller was highly recommended!

By the way, in Europe where our products must pass these CE testings, certain mains undervoltage situations are simulated, like dips etc. And if your microcontroller board doesn't have one of these extremely helpful reset contollers, it will fail the test very probably!

Simple RC-reset circuits are not producing any reset signal, when an undervoltage situation occures!!! It will give you only some simple power-on reset signal, when your board is powered-up. But only if powering-up sequence is ideal, means no fluctuations, no longer lasting bounces, etc.

Beside the fact, that the absence of reset controller increases danger of not correctly starting of micro, 89C derivatives also are in danger to loose stored program code!!! So, not using reset controller with 89C series is not only risky, but stupid and demonstrates very bad engineering practice. Every designer ever having had problems with resetting would never again omit such reset controller!

Kai