《数字电》英文版 chapter5-1-1 Synchronous Sequential Circuit

Synchronous Sequential Circuit Chapter 5 ●●●●● Analysis ●●●● ●●。●●

Synchronous Sequential Circuit Chapter 5 Analysis

●●●●● Analysis ●●●● ●●0 ●●● ●●●● Analyze existing circuits to determinel their function Synchronous sequential circuit o the basic modeling structure Two circuit models: Mealy model Moore model o Three approach used to describe the circuit: Logic function equation State table State diagram

Analysis Analyze existing circuits to determine their function ⚫ Synchronous sequential circuit ⚫ The basic modeling structure ⚫ Two circuit models: Mealy model & Moore model ⚫ Three approach used to describe the circuit: ⚫ Logic function equation ⚫ State table ⚫ State diagram

Universal model :99 System ●●● ●●●● Input Variables工 System Combinational output ogIC Variables State Excitation Variables Variables 0 Memory Fli flops E CLOCK

Universal model System output Variables O0 Om Er Excitation Variables E0 Combinational logic System Input Variables I0 In S0 Sx State Variables Memory Flip￾flops CLOCK

●●●●● Analysis principle : gpo ●●●● Determine the system variables: input, state and output o Assign names to the variables if they are not clear from the logic diagram Determine the flip-flop type. Write the characteristics equations Write the excitation equations by inspection from the logic diagram Write the output variable equations Determine whether the circuit is a Mealy or a Moore machine

Analysis principle ⚫ Determine the system variables: input, state and output. ⚫ Assign names to the variables if they are not clear from the logic diagram. ⚫ Determine the flip-flop type. Write the characteristics equations. ⚫ Write the excitation equations by inspection from the logic diagram. ⚫ Write the output variable equations. Determine whether the circuit is a Mealy or a Moore machine

●●●●● Analysis principle。 ●●● ●●●● o Mealy model machine E=f(工,St St+1=f(St, E)flip-flop characteristics equation .0=9(I, St) ● Moore mode| machine E=f(工,St) St+1= f( St, E) flip-flop characteristics equation O=g(5+)

Analysis principle ⚫ Mealy model machine ⚫ E = f( I, St ) ⚫ St+1 = f( St, E ) flip-flop characteristics equation ⚫ O = g( I, St ) ⚫ Moore model machine ⚫ E = f( I, St ) ⚫ St+1 = f( St, E ) flip-flop characteristics equation ⚫ O = g(St )

●●●●● Analysis principle :g8.o ●●●● o Write the next state equations for each state variable, using the flip-flop characteristics equation and the circuit excitation equations or construct the excitation table from the excitation equations Construct a transition table. Identify all of the states possible for a given number of state variables o Assign symbols to the states and construct a state table or state diagram When possible, construct a timing diagram

⚫ Write the next state equations for each state variable, using the flip-flop characteristics equation and the circuit excitation equations, or construct the excitation table from the excitation equations. ⚫ Construct a transition table. Identify all of the states possible for a given number of state variables. ⚫ Assign symbols to the states and construct a state table or state diagram. ⚫ When possible, construct a timing diagram. Analysis principle

Analysis flowchart:° ●●0 ●●● ●●●● Logic circuit Output variable equations &excitation equations table algebra Next-state truth table Next-state equations flip-flop Flip-flop Characteristic table State diagram Characteristic state table equation Describe the circuit by a timing diagram and statement

Logic circuit Output variable equations &Excitation equations Next-state truth table Next-state equations flip-flop Characteristic table State diagram &State table Describe the circuit by a timing diagram and statement Flip-flop Characteristic equation table algebra Analysis flowchart

Example 6.2 ●●●●● ●●●● ●●0 ●●● ●●●● projecTile =L/(t2-t1) t2 STARTN STOPN START STOP Start/stop sensor

Example 6.2 Start/stop sensor START STARTN STOP STOPN t1 t2 L Vprojectile = L/ (t2-t1)

Example 6.28988 ●●0 ●●● ●●●● Start/stop sensors As the bullet passes over the start sensor, the start signal (SRT) is generated When the same bullet passes over the stop sensor, the stop signal (STP) is generated STARTN STOPN START(SRD) STOP(STP) Start/stop sensor

⚫ Start/ stop sensors ⚫ As the bullet passes over the start sensor, the start signal (SRT) is generated. ⚫ When the same bullet passes over the stop sensor, the stop signal (STP) is generated. Example 6.2 Start/stop sensor START (SRT) STARTN STOP (STP) STOPN

Example 6.2 ●●●●● ●●●● ●●0 ●●● ●●●● ● BCD counter: ●t2-t1 o measure the elapsed time of the bullet directly by counting the number of clock pulse

Example 6.2 ⚫ BCD counter : ⚫ t2-t1 ⚫ measure the elapsed time of the bullet directly by counting the number of clock pulse