Dear all,
i hope this message finds you well, i'm an a second year electrical engineering student and i required to create a logic design project which is a parking counter system that does the following: We have 4 zones A,B,C and D, each zone can have up to 10 cars, i'm required to do a system that have a 4 buttons on the entrance once i click on the entrance the counter must increment by one and another buttons on the exit so when i press it it decrement plus i must show the number of cars presented in each zones using 7 segments display plus also showing the word full when the zone is full and half when only we get 5 cars and empty when no cars are in using 7 segment display. I have a serious problem with the decrement, it is incrementing instead of decrementing, i'm really out of time because finals are next week and the submission of the project is after 2 days. Below you find attached the project requirements.

 

hi A,
Please post your logic diagram so that we can advise any changes.
E

 

Sorry i didn't post it first. Any help is really appreciated

 

What are your inputs? Are they floating? Specifically, what is the voltage at AEntry when nothing is happening at the entrance?

Read the notes on the datasheet. You might find out what's going on there...

Your lockout logic (to prevent more than 10 cars per zone) is contributing to the problem.

Try it with the AND2 gate bypassed for a test.

 

I noticed that i've missed placing the inputs. My suggestion is to place push buttons on the entry and the exit, so when pressed it will give a value of one otherwise zero, so when nothing is happening at the entrance the voltage at Aentry is zero. So i think if i placed Aentry direclty to the up pin and the down pin to A exit and the input A to the logical gate Aentry nor Aexit i would reduce the problems presented, plus connecting the clear button to a push button and the load to the Vcc. Seems legit?

 

Hard to tell in detail without an updated schematic. But I can tell that you did not read the datasheet as I had asked. Do that next and come back with your findings.

 

Oh, and I am assuming this is your homework. We have a subforum for that.

 

I'm working on it now. I'm doing it only for zone A.

 

i'm really out of time because finals are next week and the submission of the project is after 2 days.

Are you working on this project alone?

How long have you been struggling with it before seeking help?

4 days won't be enough time for anyone here to help you because we won't do the work for you. It would be unethical for us to help you cheat and it deprives you of the opportunity to learn.

 

Hello Dennis,
i'm working on this project with my classmate. We did the design on paper and made all the possible simplifications and truth tables. But the problem is that we brought a counter that is not doing what we want on quartus software, we are new to counters and especially this type. The design seems perfect but the simulation on quartus is not what we expected we tried several cases and many possibilities we approached sometimes to what we need but with some unresolved issues. I'm not asking to do the work for me, i'm just seeking help to use the counter and to get advise from experts not more, and i came here after i lost hope and tired from trying.

 

We bought the 74sl193 counter that we can't replace, and we never used this counter before or used a chip with dual clock. It is our very first time using such IC and i've been trying on Quartus since Wednesday.

 

It will work for you, but you need to be familiar with how it operates. That's why I keep emphasizing that you must read the datasheet. Have you done so? It is easily accessible on the Internet by searching for "74193 Datasheet". Look at page five of this particular datasheet, and read it carefully. Make sure you understand the diagram.

Listen, I'll even give you the link

Oh, and your design is not perfect.

 

the problem is that we brought a counter that is not doing what we want on quartus software, we are new to counters and especially this type.

What is the simulator giving that you don't like?

What are you supposed to do with all inputs?

That counter will be fine. Your instructions didn't say how to handle a situation where someone chose to park in a zone that was already full. Or how to handle the case where someone parked in the wrong zone. You can state in your assumptions that drivers do what they said they would.

 

I'm done for today. I tried many cases and changed the first level logic i even changed the counter and used 4-bit up/down counter but i didn't reach anything new. I will continue tomorrow but i'm not sure what the problem is. Anyway, thank you for your help and time.

 

I will continue tomorrow but i'm not sure what the problem is.

I ask again. What is the simulator doing that you don't like? What were you taught to do with all inputs to an IC?

You're short on time and are not close to a solution. It's time to start burning the midnight oil...

 

i must show the number of cars presented in each zones using 7 segments display plus also showing the word full when the zone is full and half when only we get 5 cars and empty when no cars are in using 7 segment display.

You have misread the instructions. Using 7 segment displays is for extra credit and you're to show the number of cars in a zone, not "full", "half", etc.

Which is strange because showing the number of cars requires less logic (aside from the BCD to 7 segment decoder) than using 3 LEDs. Which, BTW, you have implemented incorrectly. What happens when there are 4 or 6 cars in a zone?

 

Showing the number of the cars presented in each zone is the bonus. But we must use 7 segments display. In my design i didn't yet implement the part of the design showing the number of cars. I'm still stuck in the counter part. This is my first time using the counter. I'm not getting the Full, nor the half and nor the empty when simulating, there is glitches and hazards. I don't know what to do especially that i have other tasks to do.

 

I'm not getting the Full, nor the half and nor the empty when simulating, there is glitches and hazards.

First, are you certain that the counter is counting? You don't show enough logic for us to be able to tell. You also have unconnected inputs, and I've asked you several times now what you were taught to do with all inputs; and you have not responded.

I don't know what to do especially that i have other tasks to do.

That comes with being a student. The more important thing is how much time were you given to do this assignment? If you're required to breadboard the circuit, 4 days probably isn't enough time for a 2nd year student.

 

I'm doing this now just to get familiar with the counter.

 

I'm doing this now just to get familiar with the counter.

You still don't have anything connected to reset.