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colltoaction/synchronous_counter_design.md

Last active August 29, 2015 14:11
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Synchronous counter design
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synchronous_counter_design.md

Synchronous counter design

When designing a synchronous counter, you first draw the counter's state diagram.

With that in mind, you can write the transitions table, where:

  • the independent variables are the current flip-flops' outputs Q[0], Q[1], ... Q[n]
  • you provide the desired next state of the flip-flops' outputs Q[0], Q[1], ... Q[n]
  • the dependent variables are the flip-flops' entries FF[0], FF[1], ... FF[n], which depend on the current state, the desired state, and your flip-flop type
  • there may be extra independent variables like a reset entry, or an up/down entry for an up/down counter

You put combinational circuits in front of your flip-flops' entries. You may use Karnaugh to simplify them.

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