1 CSULB -- CECS 201 – A Primer for FSM’s © 2014 R.W. Allison

2 1) The most fundamental memory cell is called a “Flip-flop” (FF) Memory is an “array of registers,” used to store binary data. A flip-flop is a one-bit memory cell, used to store one-bit of binary data. 2) The most fundamental synchronous logic component is called a “Register” 3) All computer systems have various types of Memory to store instructions & data 4) Sequential Logic Conversely, “sequential” logic, also known as “clocked” logic, has outputs that are dependent upon BOTH the present inputs and the present state. Up to this point, we’ve studied “combinational” logic, where the outputs are ONLY dependent upon the present inputs. 6) Finite State Machines (FSM’s) FSM’s, used to solve a myriad of computer design problems, are a kind of sequential logic where the “present state” of the machine is stored in a “state register” A register is an array of “n” flip-flops,” used to store “n-bits” of binary data. CSULB -- CECS 201 – A Primer for FSM’s © 2014 R.W. Allison

3 1) All FSM’s can been designed using three “blocks” of logic The “first” block of logic is referred to as the “Next State” logic and is “combinational” CSULB -- CECS 201 – A Primer for FSM’s © 2014 R.W. Allison The “second” block of logic is referred to as the “State Register” and is “sequential” The “third” block of logic is referred to as the “Output” logic and is “combinational” Next State Logic Output Logic State Register Inputs Outputs NS PS clock