how to set up a toggle flip flop

Thread Starter


Joined Jun 18, 2007
To refine an earlier post.

My situation can be presented in the following example. I have a machine that fires a cannon. To prevent a misfire, there is an arming button, or set/reset button. The trigger will not work if the device is not set. When the device is set, then the fire button must be pressed to fire the cannon. Once the fire button in pressed, the system is reset.

What I understand so far is that I need to use a toggle flip flop and an AND logic chip. When the flip flop is set, the output is high and satisfies one condition of the AND chip. The second condition of the AND is satisfied when I press the fire button. This much I understand.

After reviewing some textbooks and web pages, I am still unclear as to what inputs and outputs need to be connected on the flip flop. Assuming that there is a D, Clear, Clk, Preset, and Q and Qnext, pins. What is going on with this?

I know that the set/reset button as well as the fire button need to be able to toggle the system.

Could someone tell me straight forward, button A connects to pin X, and that give output from pin Y. etc.

Any help is appreciated.


Joined Feb 24, 2006
Any JK or JK-bar FF can be setup as a toggle flip-flop by tying the inputs to the appropriate state and clocking away.

Are you a JK designer, or a D designer?


Joined May 19, 2004
a toggle flip-flop is a j-k flip-flop with the j and k inputs tied high. when provided with a valid clock the outputs will toggle - set - reset - set - and so on.

but, i don't see why a simple and gate with the 2 inputs - a-) from your "arm" button and b-) "trigger" button to equal "fire" output y-).

do the buttons exist now? do you need latching? explain more if this isn't right for you.