Baisic flip-flop circiut

Baisic flip-flop circuit

Hi!
I'm a total newcomer in terms of electronics, and i have this problem to solve for classes. I tried to do it by myself but i'm not absolutely sure what that thing should do...

Problem:
Design the one input and one output sequential circuit that implements the following state
transition and output tables.
State Transition Table
Input
State 0 1
S1 S2 S3
S2 S2 S3
S3 S3 S1
Output Table
Input
State 0 1
S1 0 0
S2 1 0
S3 0 1
You can use D or J-K flip-flops and NAND, NOR and NOT gates.

So.. First of all, how many inputs there should be? Only for clock or for clock and an input? And how the transition table works? It depends on a clock or on input? ah.. I'm so confused. Where should i start?

p.s.
Sorry if this is a wrong part of forum.

I can help you

But i am not sure about this part of the question
---------------------------
Input
State 0 1
S1 S2 S3
S2 S2 S3
S3 S3 S1
Output Table
Input
State 0 1
S1 0 0
S2 1 0
S3 0 1
---------------------------
Can you post more preciously they way you got it?

But some of your questions can be answered now.

1. how many inputs there should be?
Your question itself tells one input and one output. So there should only one input. The question is to design sequential circuit so clock must be applied. But this will not count as an input.

State table is a way to represent the state machine. It tells you for all possible inputs, how the state transition should happen. A hypothesis example.

input -----current_state ---- next_state
1 ------------ S3 --------------- S1
1 ------------ S1 --------------- S2
0 ------------ S2 --------------- S3

in above table when input is '1' if the current state is S3 then it should go to S1, (OR) if current state is S1 then it should go to S2. If input is '0' , if current state is S2 then it should go to S3.


From your question, in your state machine there must be three state S1,S2 and S3.

i did't got it, it was given by the teacher,and i don't know what that circuit should do . Ok, and the state changes when i change the clock, right? Thanks for help man, i really don't know where to start.

OK what are you studying? tell me your background. Then we will start discussing about this.

i'm a first year computer science student. And this is my 4th exercise form computer architecture. the previous 3 was ease, and this one is like WTF for me :].
I have to prepare this thing, and build it in in classes . Oh, and English is't my first language so sorry for all of the mistakes

otis said:

But i am not sure about this part of the question
---------------------------
Input
State 0 1
S1 S2 S3
S2 S2 S3
S3 S3 S1
Output Table
Input
State 0 1
S1 0 0
S2 1 0
S3 0 1
---------------------------
Can you post more preciously they way you got it?

Click to expand...

basically, when state is in S1, it moves to S2 if input=0, moves to S3 if input=1.. and so on.
And when state is in S1, it outputs 0 if input=0, and outputs 0 if input=1 and so on..

A simple 2x4 truth table should solve this problem.

i did a truth table, it looks like this:
Current In. Next State Output
S1------0------s2----------0
S1------1------s3----------0
S2------0------s2----------1
S2------1------s3----------0
S3------0------s3----------0
S3------1------s1----------1

First of all, i dont know if this thing is ok, and what should i do next? it's my first time with flip-flops..

Assign 2 bit number to S1, S2 and S3 and reduce the logic.

ab\c 0 1
------------
00..0.....0...
01..1.....0...
10..0.....1...
just like that?
x=B|C+AC ?

something like that, but your boolean equation is incorrect, though.

ok..hm..x=(-AB-C)+(A-BC)? and where is flip-flop in all of this?
(and big thanks for everything)

Edit
i'm sorry to ask, but can someone draw the circuit for me? I have classes in 5 hours and i'm desperate.

why not try to use system verilog to implement?

never mind