電子線路基礎(chǔ)(梁明理)第8章

1、 常用的組合邏輯電路常用的組合邏輯電路74LS138譯碼器譯碼器 74LS153數(shù)據(jù)選擇器數(shù)據(jù)選擇器 74LS83四位全加器四位全加器邏輯電路邏輯電路邏輯功能邏輯功能FA B A BA BA BA BA BABABA BA BA BFA B A BA BA BA BA BFABBCACFABBCACAB BC AC YABCSABCABCYABCSABCABC8989ASSSS45674567BSSSSSSSS23672367CSSSSSSSS1357913579DSSSSSSSSSS00SABCD SABCDS8989ASSSS45674567BSSSSSSSS23672367CSSSSSS

2、SS1357913579DSSSSSSSSSS00SABCD SABCDS2765476541765435427654320765643642176543210EI=0AIIIII I I IAIII I II I II I I I I IAII II I II I I IEOIIIIIIIIGSEI EO當(dāng)時1片受片受2片控制，當(dāng)片控制，當(dāng)2片輸入無片輸入無0時選通時選通2片選通片選通不編碼時輸出為全不編碼時輸出為全1，兩片的輸出相，兩片的輸出相與，輸出為編碼片與，輸出為編碼片的輸出，互不影響。的輸出，互不影響。編碼最高位輸出，編碼最高位輸出，在本片時為在本片時為0，不在本片時為不在本片時為

3、1 因此，因此，012A2BYG GGC B A012A2BYG GGC B A112A2BYG GGC B A112A2BYG GGC B AX X X 0 103210LA A A A03210LA A A A13210LA A A A321020321020aA A A AA AA A A AA A210210bA A AA A A210cA A A210210210dA A AA A AA A A021eAA A2110230fA AA AA A A321210gA A A A A AA0 A1 A2 A3地址輸入端地址輸入端數(shù)據(jù)輸入端數(shù)據(jù)輸入端數(shù)據(jù)輸出端數(shù)據(jù)輸出端使能端使能端() E

4、N (i0,1,2,3)iiym D10A A10A A10A A10A A21002101210221032104210521062107001122334455667770()()()()()()()()()iiiYA A A DA A A DA A A DA A A DA A A DA A A DA A A DA A A Dm Dm Dm Dm Dm Dm Dm Dm Dm D110110nnBB BAA A逐位比大小A BA BA BFABFABFABABAB1333312222223111134000041234 (=1) (=1) (=1) (=1)A BGABABGGABABGG

5、ABA BGGABABGFG GGG當(dāng)時，當(dāng)時，當(dāng)時，當(dāng)時，579115791153333571223322791211332211911123003322110011 (1) (=1) (=1) (=1) (=1) (=1) (=1)A BFG G GGGA BA BGGG A BA BA BGGG GA BA BA B A BGGG G G A BA BA B A B A BG其中當(dāng)時，當(dāng)，時,當(dāng)，,時,當(dāng)，,時，= =iiiiiiSABCABAiBiSiCi00110101011000011111iiiiiiiiiiiiiSA B CA B CA B CABC111iiiiiiiCABA

6、CBC1111iiiiiiiiiiiiiSA B CA BCA B CAB C111iiiiiiiCA BA CB C1111iiiiiiiiiiiiiiSSA B CA BCA B CAB C111iiiiiiiiCCA BA CB C1111iiiiiiiiiiiiiiSSA B CA BCA B CAB C111iiiiiiiiCCA BA CB C1111iiiiiiiiiiiiiiSSA B CA BCA B CAB C111iiiiiiiiCCA BA CB CiiiiiiAABBCC1()iiiiiiCABAB C1111111111111()()()()()()iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiSA B CA B CA B CABCB ACACB ACACB ACB ACB ACB ACABC112471247235673567LABCABCAB