If you look at your circuit in real life circumstance, then key A should be door closed, and key B should be driver seated, otherwise, if the driver gets in the car and gets back out, and shuts the door, then already 2 inputs have been satisfied, so now the circuit is activated to that point, especially if the window was down for hoim to put the key into the ignition...and so on...

but making the door shut be key A then if the driver sits down, and gets back up out of trhe car, then the switch is released and no output happens at the first gate. Until he sits down again...

And so on...

Now if this really had to be designed, then a fail safe network would need to be implemented for every possible scenario. such as a reset when the driver gets out of the seat, or else he will now be able to start the car with the door opened, so a reset would need to be in the first order of the branch, such that if he gets back out, then the switch would activate a reset and so on ....
Also another reset should activate when both, the ignition is turned off, and the door is opened AND then shut.

Just one more thing yet, you would get a good grade on this if you designed it to take into consideration as much failsafe features possible.

Look at every scenario, of switch inputs and design it to work in proper sequence every time.
That wouild be using logic gating to call the reset inputs as well.

Are you getting an understanding of logic networking with this, now, with these examples?

 

Ok so I tried to do it myself using D Flip Flops this time. I don't have a problem getting it to get a high output, but I still dont understand what to do in order to make things need to occur in a sequence.

Did you study my circuit? Do you understand the purpose of every component I inserted? Do you see how the correct order of activation is ensured?

Please answer thoroughly so that we can help you effectively.

 

Yes, I did study your circuit very good. We have not gone over the quad bus buffer yet and are not allowed to use them in the design so I am not quite sure on how to get around them. The only things we can use are jk and d flip flops, inverters, and gates, or gates, nand gates and nor gates. We also havent gone over pull up resistors yet, and according to my professor I shouldnt need to use them in the circuit. I spent about 3 hours today going through my circuit trying different things and got a little closer, but not fully there. Im doing some more reading tomorrow so hopefully I will be able to figure a bit more out.

 

I already told you how to overcome the buffer by using a MUX in the last paragraph of post #10.

As for the pull-up resistor, if you use a MUX, you don't need one on the RESET pin. To get rid of the pull-up resistors by the switches, replace the push buttons with switches that have 3 pins, that will give Vcc if on and Ground if off.

 

Yes, I know you told me how to overcome the buffers, but I am not able to use MUX nor have we learned about them yet which throws that whole idea away for me. I will look into the switches and figure those out. Thank you

 

I find it an overkill to use more FFs to control the reset. That's an awfully limited project.

Well, if it can't be helped, design the control circuit with FFs. You need a circuit that will do the same job as the 3 state buffer was there to do. Drive its output high if input A is raised before input B. Good luck!

 

But you can easily make a mux from some AND gates and some inverters, and you can use a big hairy OR gate instead of the tristate buffers.
/mike