It is well placed advice to use a quality RESET generator for ANY microcontroller. R/C or C type reset circuits have been problematic almost since the beginning of microcontrollers. I recall working with Keytronics a long time ago (1983) on a custom keyboard design and it used an 8048/8049 controller. Even on these NMOS devices the R/C type reset was garbage and unreliable. In those days there were not nice chips to do the generator function so had to make my own out of reference voltage and a low voltage comparator.

But I can tell you it was rather disgruntling to turn on the office automation system I was designing and have the keyboard fail to initialize part of the time when Keytronics wanted to use thE R/C type reset.

Michael Karas