4 bit multimode counter. Help

dl324

Joined Mar 30, 2015
9,985
Welcome to AAC!

Show what you have so far for state diagram and truth table so we can see where you need help.
 

dl324

Joined Mar 30, 2015
9,985
You'very only drawn half of the state's and don't show the up/down input.

Your state table only shows half of the data.
 

ci139

Joined Jul 11, 2016
1,177
there is "2" possibilities to make this
  • make two separate counters and mrege them as well as you can
    the easiest (not optimal way to do this is to MUX the control inputs of the Flip-Flops)
  • include MODE bit as an input entry and make 1 complex counter
    e.g. -- write the state map for the entire range of the I/O + (perhaps) the internal control states
  • there are likely more principles to approach this problem
    i don't read out from your task description whether it should be sequential or synchronous -- so you likely can choose that one and yourself
 

dl324

Joined Mar 30, 2015
9,985
That is where i am stuck. What other half is missing?
Your table shows binary up and gray down, so you're missing binary down and gray up.

Your state diagram only shows binary up/down, but it doesn't show the input that controls direction. The format isn't like anything I've seen before. Usually each state is in a circle.

EDIT: I just noticed that the directions don't specify the type of flip flop you're supposed to use. Can you use anything you want?
 
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dl324

Joined Mar 30, 2015
9,985
Are you making any progress?

Are you required to draw both counters in the same state diagram? I'm not a fan of state diagrams for counters, but tried and it got messy pretty fast.
 
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