#### dididan2000

Joined Mar 21, 2017
15
Hi. Please help me!! I have a project with my partner. It has taken my class two weeks so far, but my partner and I are definitely behind every other group. Our project is simulating a deli number counter. This is the circuit that we are building off of. Where it says switches, rather than those pins on the end, we need to create an SSI D flip flop asynchronous counter that goes from 0 to 8. Where it says buttons, we need to do the same but have an MSI D flip flop asynchronous counter that goes from 0 to 9. Essentially both of them together go to 80 maximum and everything beyond that resets to 0. We are also required to have a clear set for both where anytime you clear it, it sets the whole thing back to 00. I am so confused and our teacher does not like being asked for help. Someone please help me. My partner and I are falling behind and we are obviously not the greatest students in the class. We have no idea what to do. Thank you.

#### WBahn

Joined Mar 31, 2012
30,286
So take it one piece at a time. You know that you need to make an asynchronous counter that counts from 0 to 8 and that can be reset to 0.

Make one of those and test it.

For your purposes, what distinguishes and SSI counter from an MSI counter? It's hard to tell because you say that both are supposed to use D flip flops. Are you sure you aren't supposed to us an MSI counter IC for that second one?

#### dididan2000

Joined Mar 21, 2017
15
So take it one piece at a time. You know that you need to make an asynchronous counter that counts from 0 to 8 and that can be reset to 0.

Make one of those and test it.

For your purposes, what distinguishes and SSI counter from an MSI counter? It's hard to tell because you say that both are supposed to use D flip flops. Are you sure you aren't supposed to us an MSI counter IC for that second one?
Right that's what I meant with MSI. An IC. And to reply to your first part, that's the problem. My teacher like barely teaches us how to do anything and expects us to then know everything and drops projects like this often but it hasnt been to this hardness level. See the problem is I really don't know hot I make an SSI D flip flop asynchronous counter that goes from 0 to 8. Where do I start? All I know is that you need 4 flip flops lol. I'm sorry but like that's literally all I know at this point. I'm sorry if I'm stupid but yeah

#### WBahn

Joined Mar 31, 2012
30,286
So you guys haven't covered counters at all?

Counters aren't covered in your text at all?

Googling something like "asynchronous counter" hasn't produced any useful information at all?

#### dididan2000

Joined Mar 21, 2017
15
So you guys haven't covered counters at all?

Counters aren't covered in your text at all?

Googling something like "asynchronous counter" hasn't produced any useful information at all?
We did cover it all sort of but my teacher does it fast and doesn't explain anything which leaves us with the question: "What?" I have passed this class through guesswork about 80% of the time. Every time I look up 4-bit asynchronous counter on google only jk flip flops come up and if I look them up with d flip flops, it's either really generic and doesn't tell you how to edit it to go to a certain number or it's a 3 bit

#### dl324

Joined Mar 30, 2015
17,095
Do you know how to make a 4 bit asynchronous binary counter with D flip flops?

#### djsfantasi

Joined Apr 11, 2010
9,185
Perhaps you are searching for the wrong thing! It took me about 15 seconds to pull up a page with a design and schematic for a 4 bit asynchronous counter with D flip flops.

Don't search so specifically. I searched for "D flip flop counter".

I am also surprised that you can't generalize the schematics for your purpose.

#### LesJones

Joined Jan 8, 2017
4,226
Have you considered using a divide by 16 counter and not using the top bit ?

Les.

#### dididan2000

Joined Mar 21, 2017
15
Perhaps you are searching for the wrong thing! It took me about 15 seconds to pull up a page with a design and schematic for a 4 bit asynchronous counter with D flip flops.

Don't search so specifically. I searched for "D flip flop counter".

I am also surprised that you can't generalize the schematics for your purpose.
Ok I made the d flip flop ssi. It supposed to go to 8 but I got it to 7. I not know how I would do 8.

#### dl324

Joined Mar 30, 2015
17,095
Ok I made the d flip flop ssi. It supposed to go to 8 but I got it to 7. I not know how I would do 8.
Post a schematic.

#### dididan2000

Joined Mar 21, 2017
15

#### WBahn

Joined Mar 31, 2012
30,286
What's a schematic
It's that picture-like thingy that you included in your first post.

#### WBahn

Joined Mar 31, 2012
30,286
Ok I made the d flip flop ssi. It supposed to go to 8 but I got it to 7. I not know how I would do 8.
Why do you keep using the terms SSI and MSI as if they are something that YOU are making?

Do you have any idea what these terms mean?

#### absf

Joined Dec 29, 2010
1,968
What's a schematic
Our teachers used to teach us to call that "Circuit Diagram". It is the same as "schematic" in this forum.

In my Oxford study dictionary, "Schematic" says 'adj. In the form of a diagram or chart. schematically adv'

I think you need a technical dictionary to find the word listed as a noun.

Allen

#### dl324

Joined Mar 30, 2015
17,095
Essentially both of them together go to 80 maximum and everything beyond that resets to 0.
Does the counter actually count to 80? Or does it reset to zero after 79?

When you say "everything beyond that resets to 0", does that mean the counter stops incrementing? Or does it roll over?

#### djsfantasi

Joined Apr 11, 2010
9,185
Have you figured out how to count to 8 yet? You said you can count to 7; how many flip flops are needed to count to 7? How many bits are needed? If you need a larger number or 7+1 in this problem, how many bits will you need?

#### dididan2000

Joined Mar 21, 2017
15
Have you figured out how to count to 8 yet? You said you can count to 7; how many flip flops are needed to count to 7? How many bits are needed? If you need a larger number or 7+1 in this problem, how many bits will you need?
Mine is 4 bit, but the last flip flop I didn't make it effective because then it goes to like 14 or 15. So I don't know how to to get it in the middle and go to 8

#### djsfantasi

Joined Apr 11, 2010
9,185
The secret search phrase that is about to be revealed to you should teach you how to solve your problem. Read some of the articles and then come back with an update for us.

module n counter

#### WBahn

Joined Mar 31, 2012
30,286
Or perhaps try "modulo n counter" instead.

Can you take your four-bit counter and modify it so that you have an additional input that resets the counter back to 0?

Can you take your four-bit counter and add a bit of additional circuitry that produces a HI when the counter's value is 8? (or make it 9 for right now).

#### djsfantasi

Joined Apr 11, 2010
9,185
Or perhaps try "modulo n counter" instead.
Dam autocorrect! I had retyped that three times.