Re www.embedded.com/story/OEG20030115S0042

I am a member of Jacks fan club, but in this he is missing one point:

A runaway program can easily end up toggling a port pin and thus keep an external puppy alive.

The better internal dogs (e.g. Philips P89C66x) 1) can not be disabled and 2) require 2 consequtive writes with different data not to bite.

With such an internal dog it is much less likely (read impossible) to keep the puppy happy in runaway code.

Erik