# Logisism Help - Building D Flip-Flop

I'm using the program Logisim to create very simple circuits as I am just beginning to learn about the different logic gates and such.

In the Logisism program it has in-built features already such as a Counter, Register, D Flip-Flop etc. I'm trying to create a D Flip-Flop without using the inbuilt features and instead using the logic gates that make it up. I know a D Flip-Flop looks like this:

So I created it like the above picture in Logisism, I'm wondering how I can add Clear functionality where if CLEAR is equal to 1 then it resets it.

Another queston I have is using the Logisism program, the in-built D Flip-Flop looks like this:

It has input CLOCK and D with Q and NOT_Q output with a CLEAR. When I try to go to create a sub circuit from the D Flip-flop I made above, it doesn't provide a CLOCK input:

It just has D input and Q, NOT_Q outputs. How do I make CLOCK an input?

• Clear is setting Q to zero, right? I.e. the very same thing D=0 with CLK active doing. So simulate it. As for the second question - if I remember correctly, you can enable different inputs in the parts preferences sheet. May 2 '16 at 13:42