# Sequential circuits help

Discussion in 'Homework Help' started by Andreea Blaga ت, Sep 4, 2015.

1. ### Andreea Blaga ت Thread Starter New Member

Jun 26, 2015
15
0
Hello,
I am currently studying for my exam, and I got few exercises left. I came across this exercises that I really don't know how to solve neither I found the solution anywhere.
"A sequential circuit has one input (X) and one output (Z). Design a digital system that makes the output Z = 1 if and only if the total number of 1's received is divisible by 3 (for example, 0, 3, 6, ) or total number of 0's received is an even number greater than zero (nine states are sufficient)."
I have no idea how to solve this. Does anyone know something about it?
Any help will be much appreciated, thanks in advance.

2. ### WBahn Moderator

Mar 31, 2012
17,446
4,699
Try tackling them one at a time.

Design a machine that will output a HI if the number of 1's received is divisible by 3.

Then design a machine that will output a HI if the number of 0's received is an even number greater than 0.

How could you combine the output of these two machines to give the desired final result requested?

3. ### RBR1317 Active Member

Nov 13, 2010
202
39
This is a sequential circuit so it will be clocked. Do you need to design the data input clocking circuit, or can you assume that a "1" input will advance the "1" counter and a "0" input will advance the "0" counter?

4. ### Andreea Blaga ت Thread Starter New Member

Jun 26, 2015
15
0
It doesn't really say how to implement it, just to design it, but i think the second one would be more appropiate.

5. ### Andreea Blaga ت Thread Starter New Member

Jun 26, 2015
15
0
I believe with some logic gates or multiplexers to choose between the two?

6. ### WBahn Moderator

Mar 31, 2012
17,446
4,699
So take the first step -- design a machine that will output a HI if the number of 1's received is divisible by 3 (or do the other one first -- your choice).