CS137-lecture-20210318

FSM cont. #

Design rules #

  • If we cannot determine function(s) of combinational circuit(s) in advance:
    1. Model FSM as FSD
      • May need to design bit-slice 1st
    2. Determine number of flip flops (dependent on the number of states you need)
    3. Convert the FSD to truth table
    4. Find minimal expressions for next state variable(s) and output(s)
    5. Draw the complete circuit with flip-flops
  • Otherwise
    • Use bit-serial design with known modules
    • Or, bit-parallel design with known modules

Example #

Lets design a Moore state machine that accepts the string \( 101 \) .

As a box diagram:

image_2021-03-18-19-20-24

Step 1, create a finite state diagram:

image_2021-03-18-20-08-09