Hi there,
I am currently designing a 12 hour alarm clock.
As i am new to logic circuit design i have been restricted to using only these basic components - gates, wires, LEDs, hex displays, counters, pins/buttons, splitters, and flip flops.
I'm currently in the stage of configuring the hex digit displays to show 12 hour time appropiately. I have run into a bit of a wall in regards to configuring the 2nd hour digit, which of course must count 0-9, triggering the first digit to 1 as it hits 10, and then 0-2 as the first digit is triggered to 1, and then back to 0. Please find attached a SS of my circuit, any advice in regards to this issue would be greatly appreciated. I can drop the file if needed too.
View attachment 346617

 

Hello.
I hope the video series below helps.

 

Welcome to AAC!

I can drop the file if needed too.

This is the Homework Help forum. You need to post your work before members can offer assistance.

From your use of 'splitters', it seems that you're using Logisim. Post your .circ file. You'll have to rename the extension to .txt (or something allowed) to be able to post.

An explanation of what the circuit is doing incorrectly will also be helpful.

View attachment 346617

Attachment isn't found.

 

Apologies, heres the file

 

heres the file

Why are you using 4 flip flops for the M10 and H10 counters? Why are you using the reset inputs?

What is the hours counter doing wrong?

 

the second digit of the hours is reading 0-9, i need it to trigger the first digit to 1, and then the second digit needs to read 0-1. At the moment it is only reading 0-9.

 

the second digit of the hours is reading 0-9, i need it to trigger the first digit to 1, and then the second digit needs to read 0-1. At the moment it is only reading 0-9.

I would have designed the hours as a 1-12 counter using 4 flip flops and used a binary to BCD converter to drive the 2 hex displays. That way you wouldn't have to deal with using the set and reset inputs on the flip flops.

The binary to BCD converter can be done with gates or a ROM.

The 4 counters you've designed all seem to be the same circuit, but there are 3-4 different layouts. Why?

 

Unfortunately i dont think i'm permitted to use BCD converters, perhaps ill have to configure this manually. Im quite new to circuitry so please forgive any redundancies/errors in the current circuit haha

 

dont think i'm permitted to use BCD converters

You can make one with about 20 gates.

Im quite new to circuitry so please forgive any redundancies/errors in the current circuit

Learn to be neater. It will make it easier for others, and you, to read it. If something is the same, draw it the same way so pattern recognition can be used.

the second digit of the hours is reading 0-9, i need it to trigger the first digit to 1, and then the second digit needs to read 0-1. At the moment it is only reading 0-9

Your hours counters are counting 0-19 because you're decoding 2 on the 10's counter and resetting the counters.

A redraw of your hours circuit with smaller gates and unnecessary whitespace removed. I also reordered the counters to avoid wire crossings on the displays.


Can you post the complete text for the problem? You're using the JK flip flops with J and K tied together. That defeats the purpose of using them.

Could you post your Kmaps and equations for the counters?

 

Sure, heres the slightly updated

 

Sure, heres the slightly updated

I meant instructions for the problem.

You're still using binary counters for most of the counters, when decade makes more sense for S1 and H1 counters.

I see that you've now added AM/PM indicator and a start at alarm functionality.

Still so much unnecessary whitespace, unnecessary wire jogs, scenic routes, and not laying out similar circuitry the same way.

When is this problem due?

 

It was due this previous Sunday, so i had to submit what we had, although it wasnt a full functioning clock. But thanks for the help appreciate it.

 

It was due this previous Sunday

For future reference, it's best if you present the entire text of the problem so we're all on the same page. Your initial post was regarding an alarm clock, but there was nothing in the original schematic to implement it. Implementing a comparator using gates is rather tedious, but you didn't mention being able to use the comparator object. Implementing an alarm function is also tedious. It can still be done in a couple hours, but you're likely taking other courses so have to split your bandwidth.

You were also using a generic binary counter for all of the digits. It was unclear if you were supposed to design mod-10 and mod-6 counters or to use binary counter the way you were.