170 likes | 278 Views
FLIP-FLOPS CS147 Presentation. CS 147 Ying Zuo. FLIP-FLOPS. The simplest finite state machine Storage element - compensates the weakness of combination circuits - outputs depend on both current and previous inputs. (Sequential Circuit) Edge triggered
E N D
FLIP-FLOPSCS147 Presentation CS 147 Ying Zuo
FLIP-FLOPS • The simplest finite state machine • Storage element - compensates the weakness of combination circuits - outputs depend on both current and previous inputs. (Sequential Circuit) • Edge triggered (latch: level triggered)
FINITE MACHINE • A computational model consisting of a finite number of states and transitions between those states, possibly with accompanying actions.
Outputs of FSM 1. Moore Finite State Machine • Associate output with each state • Function of current state
2. Mealy Finite State Machine • Associate output with each transaction • Function of current state and its input
CHARACTERISTIC TABLES D flip-flops T flip-flops JK flip-flops SR flip-flops
State Transition Table • Also known as characteristic table. • In sequential logic, a state transition table is a table showing what state a finite state machine will move to, based on the current state and other inputs. • Four columns: current state, input, output, and next state.
Implementing this FSM using a T Flip-Flop Q(t+1) Input of T in order to get to Q(t+1) T=X*Q*+XQ
Sequential Circuit X T=Q*X*+QX Y=Q Q* Clk
Implementing this FSM using a D Flip-Flop Q(t+1) D D=X*
Sequential Circuit X D=X* Y=Q Q* Clk
Implementing JK Flip-Flop using a T Flip-Flop JK flip-flops T FFs T=JQ*+KQ
Cont. J=T K=T*