數(shù)字邏輯設計 課件 unit 10 時序邏輯分析

Unit10AnalysisofClockedSequentialCircuits

同步時序電路

異步時序電路

AnalysisofClockedSequentialCircuits

同步時序電路

異步時序電路

確定系統(tǒng)變量（輸入變量、輸出變量、狀態(tài)變量）①列驅(qū)動方程（控制函數(shù)）②列輸出方程（輸出函數(shù)）③列狀態(tài)方程（次態(tài)方程）④

列寫狀態(tài)轉(zhuǎn)換表⑤畫出狀態(tài)圖⑥畫出波形圖（如必要）時序邏輯電路的分析方法K2Q2Q2CKcp

K1

Q1Q1CKJ2J1Z“1”XJ1=K1=1J2=K2=X⊕Q1n輸入方程次態(tài)方程Q2n+1=X⊕Q1n⊕Q2nQ1n+1=Q1n③輸出方程Z=XCPQ2nQ1n

·

XCPQ2nQ1n

=XCPQ2nQ1n

+

XCPQ2nQ1n④狀態(tài)轉(zhuǎn)換表輸入現(xiàn)態(tài)次態(tài)輸出XQ2nQ1nQ2n+1Q1n+1Z000010001100010110011001100111101000110010111100Mealy型現(xiàn)態(tài)Q2n+1Q1n+1/ZQ2nQ1nX=0X=10001/011/10110/000/01011/001/01100/110/0次態(tài)方程：JK：Qn+1=JQn+kQnQ2n+1=J2Q2+K2Q2

=(X⊕Q1)Q2+(X⊕Q1)Q2

=X⊕Q1⊕Q2Q1n+1=J1Q1+K1Q1

=Q1現(xiàn)態(tài)Q2n+1Q1n+1/ZQ2nQ1nX=0X=10001/011/10110/000/01011/001/01100/110/00/00/01000110/00/11/01/01/01/1X/Z01⑤狀態(tài)圖Mealy型:輸出值畫在狀態(tài)圖轉(zhuǎn)換線的旁邊結(jié)論：模4可逆計數(shù)器X=0:加計數(shù)X=1:減計數(shù)Z：進位和借位輸出標志④狀態(tài)轉(zhuǎn)換表輸入現(xiàn)態(tài)次態(tài)輸出XQ2nQ1nQ2n+1Q1n+1Z000010001100010110011001100111101000110010111100D1Q1Q1CKD2Q2Q2CKD3Q3Q3CKcp

Y1Y2Y3D4Q4Q4CKY4D1=Y3n

Y1nY4n

=Y1nY4n

+

Y3n

Y4nD2=Y1nD3=Y2nD4=Y3n輸入方程次態(tài)方程Y4n+1=Y3nY3n+1=Y2nY2n+1=Y1n

Y1n+1=Y1nY4n

+

Y3nY4n③狀態(tài)轉(zhuǎn)換表現(xiàn)態(tài)次態(tài)序號Y4nY3nY2nY1nY4n+1Y3n+1Y2n+1Y1n+100000001①00010011②0010010100110111③01001000010110110110110001111111④10000000⑧10010010101001001011011011001000⑦1101101011101100⑥11111110⑤Moor型同步時序邏輯電路分析例：④狀態(tài)圖00000001110000111111111001111000101100100101011001001000結(jié)論：模8計數(shù)器(格雷碼輸出)，能夠自啟動同步時序邏輯電路分析例：③狀態(tài)轉(zhuǎn)換表現(xiàn)態(tài)次態(tài)序號Y4nY3nY2nY1nY4n+1Y3n+1Y2n+1Y1n+100000001①00010011②0010010100110111③01001000010110110110110001111111④10000000⑧10010010101001001011011011001000⑦1101101011101100⑥11111110⑤K4Q4Q4CKcp

K3

Q3Q3CKJ4J3K2

Q2Q2CKJ2K1

Q1Q1CKJ1Y4Y3Y2Y1異步時序邏輯電路分析例：J3=

K3=

1J2=

Y4n,K2=

1J1

=

K1

=

1J4=

Y3n

Y2nK4=

1輸入方程次態(tài)方程CP4=Y1↓

CP3=

Y2↓

CP2=Y1↓CP1↓

Y4n+1=

J4Y4n

+K4Y4n

=

Y4nY3nY2n

Y3n+1=

J3Y3n

+K3Y3n

=

Y3n

Y2n+1=

J2Y2n

+K2Y2n

=

Y4nY2n

Y1n+1=

J1Y1n

+K1Y1n

=

Y1n

Moor型現(xiàn)態(tài)次態(tài)時鐘Y4nY3nY2nY1nY4n+1Y3n+1Y2n+1Y1n+1cp4cp3cp2cp100000001無無無↓00010010↓無↓↓00100011無無無↓00110100↓↓↓↓01000101無無無↓01010110↓無↓↓01100111無無無↓01111000↓↓↓↓10001001無無無↓10010000↓無↓↓10101011無無無↓10110100↓↓↓↓11001101無無無↓11010100↓無↓↓11101111無無無↓11110000↓↓↓↓CP4=Y1↓

CP3=

Y2↓

CP2=Y1↓CP1↓

次態(tài)方程Y4n+1=

=

Y4nY3nY2n

Y3