though the inputs and outputs may not be. That's why they hae those inversion bubbles on some of the logic symbols. What you call positive and what you call negative is quite arbitrary. In the default, however, meaning unless otherwise stated, I'd guess it's all positive, with a high level being true, and low being false.

An AND is a function that, when true, asserts that all its inputs are true. A NAND is also a function that when true, asserts that all its inputs are true, though its output is negated. An OR is a function that, when true, asserts that one or more of its inputs are true. A NOR is a function that, when true, asserts that one or more of its inputs are true, though its output is negated.

All this talk about what's true and what isn't is wandering off into the realm of philosophy, by which means one can easily convince himself that the world is flat and the sun revolves around it.

Now ... go back and look at
http://www.8052.com/forum/read.phtml?id=156162
and read what I said.

I said nothing about what's true or false, only stating that an AND gate was a negative-input NOR, which it is. A NOR function, as I say above, is a function that asserts that one or more of its inputs is true, though its output is negated. What that means, in this context, is that, when one or both inputs to an AND gate is low, the output will be low. The OR function says one or the other, or both, input is true. The inversions at the inputs make the low levels true, and the inversion at the output make the output low. That does, quite exactly, what I intended.

You apparently saw an opportunity to start yet another food-fight, so off you went.

RE