www.logiccircuit.org

Hello,

Thanks for the great program. What is the Inverted Checkbox in Input Pin used for? it seems to mean invert the input bit, but it doesn't seem to do anything except putting a empty circle on the chip symbol. Thanks!

Regard,
Long

So I am assuming that you are confused about "Inverted" checkbox in the Input or Output Pin dialog.
The purpose of pin is to connect internals of the circuit with outside. When you look at symbol of circuit from outside you’ll see the pin as little dot. That dot can be a solid black circle (actually half of the solid circle) or full circle with white interior. The latest one means inverted output or input. So the checkbox is simply controls how the pin will look like on the symbol of the circuit. So here is the JK flip-flop with outputs q and ~q. The output ~q is inverted while the q is not.
I hope this clarify your question.
Eugene

So the checkbox is just for displaying the picture of the chip (either active lo or active hi.) It does not implement the logic function. To actual implement the logic function (active hi or active lo), we need to add not gate to implement the function inside the chip. Am I correct ?

Yes, that’s right. It is only visual appearance of the pin.

Thanks!
This is a very good, simple to use, and well thought-out simulator program.

V/r,
Long