数字逻辑第四章2014

1、1 第四章第四章 组合逻辑电路组合逻辑电路 2 3 4 4.1 4.1 组合逻辑电路的分析组合逻辑电路的分析 5 BABAABF BABAAB BBAABA)()( BA 6 7 8 ABCCABCBABCAF CBAABC )(CBAABC CBAABC 9 CBAABCF 。 10 4.2 4.2 组合逻辑电路的设计组合逻辑电路的设计 11 12 ABCCBACBACBAF )()(BCCBACBCBA )()(CBCBACBCBA CBA 13 14 15 ACBCBACF 16 1 17 18 19 )()()( 24131324 BBBBBBBBF 20 )()()(2 41 3 1

2、32 4BBBBBBBBF 4B 2 B 3 B 1B 3B 1 B 4 B 2B )()()(2 41 3 132 4BBBBBBBB )()()()(2 41 31 32 4BBBBBBBB 21 DACCBACBBAF )()(DBACCAB BDACACB BDACACB BDACACB 22 n i ini EEEEEF 1 21 )(21uvxyabTTHEii ii i E i H ab 21iiTT i E uvxy, i E 23 ACABCAABCAB)( i E ACBCABCC BCABCBABCAB)( ABCABCBAABCAB)( 24 25 n i i EF 1

3、 26 CBACBBAF CBACAB)( CBAACB ABCACABCB ABCACABCB ABCACABCB 27 4.3 4.3 典型组合逻辑电路的设计典型组合逻辑电路的设计 4.3.1 4.3.1 基本运算电路基本运算电路 28 29 1 11 1 iii ii i i i i i ii i CBACBACBACBAS 1 11 )()( iii iiiii i CBA CBACBA 30 1 1 1 ii i iii i ii CBCBACBAC 11) ( iiiii CBCBA 31 32 33 34 35 36 37 38 39 40 012301230123 012301

4、230123310 SSSSSSSSSSSS SSSSSSSSSSSSCC 23133 123133 1231231233 SSSSC SSSSSC SSSSSSSSSC 41 42 43 1 11 1 iii ii i i i i i ii i GBAGBAGBAGBAD 1 11 )()( iii iiiii i GBA GBAGBA 44 1 1 1 ii i i i i ii i GBGBAGBAG 11) ( iiii iGBGBA 45 46 4.3.2 4.3.2 代码转换电路代码转换电路 47 48 CBDBDCBX 49 DCCDY 50 DZ 51 52 53 54 343

5、4343 BBBBBBG 55 2323232 BBBBBBG 56 1212121 BBBBBBG 57 58 4.3.3 4.3.3 数值比较电路数值比较电路 BAF 1 ABBAF 2 BAF 3 59 )(BAB )(BAA 60 61 62 63 64 65 66 67 4.3.4 4.3.4 编码器编码器 68 69 70 0 1 ji ji II II )(ji 7 65432107 6 543210 76 5 43210765 4 3210 2 IIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIY 71 4746 4543424140 765 4 3210 II

6、II IIIIIIIIIIIIIIIIIIA 765 4 3210IIIIIIIIA 4 76532107653210 4 7653210 7653210 4 )( IIIIIIIIIIIIIIII IIIIIIIIIIIIIII 7654 76542 IIIIIIIIY 7632 76321 IIIIIIIIY 7531 75310 IIIIIIIIY 72 73 7I 0123456IIIIIII ST 74 ST S Y 70 II S Y STIIIIIIIIYS76543210 0 S Y STSTIIIIIIIIYEX76543210 ) 1(0STST 0EXY EXY 0EXY

7、 75 76 7 6 5 64 3 642 1 0IIIIIIIIIISTY 76 54 3 54 2 1IIIIIIIISTY 7654 2IIIISTY 77 10AA87AA1514AA0123ZZZZ 78 79 4.3.5 4.3.5 译码器译码器 80 81 010AAEZ 0 11AAEZ 0 1 2AEAZ 01 3AEAZ 82 83 84 85 86 010AAEZ 0 11AAEZ 0 1 2AEAZ 01 3AEAZ 87 88 89 01230AAAAEZ 0 1231AAAAEZ 0 1 232AAAAEZ 01 233AAAAEZ 01 2 34AAAAEZ 0

8、1 2 35AAAAEZ 0 12 36AAAAEZ 012 37AAAAEZ 012 3 8AAAEAZ 0 12 3 9AAAEAZ 90 91 92 93 94 14 1214 8BBBBBBBa 12 124 BBBBBb 1 2 14BBBBe 1 2 4BBBc 1 2 42 41 2 14BBBBBBBBBd 2 4 1 4 128BBBBBBBf 2 42 41 2 8BBBBBBBg 95 96 97 0120AAAZ 0 121AAAZ 0 1 22AAAZ 01 23AAAZ 01 2 4AAAZ 0 1 2 5AAAZ 0 12 6AAAZ 012 7AAAZ 0 0m

9、Z 1 1mZ 2 2mZ 3 3mZ 4 4mZ 5 5mZ 6 6mZ 7 7mZ 98 CBABCACAF 1 CBABCF 2 BCAAF 3 ABCCBCBAF 4 CBABCACAF 1 CBABCABBCA)( 6543 mmmm 6543 mmmm 99 7317312 mmmmmmF 76543765433 mmmmmmmmmmF 742074204 mmmmmmmmF 654365431 mmmmmmmmF 100 101 74217421 mmmmmmmmDi 73217321 mmmmmmmmGi 102 103 104 4.3.6 4.3.6 数据选择器数据选择器 1

10、05 3012 0 110 1 0 01DASADASADAASDAASY 106 107 108 109 110 111 BCCACBAY ABCCBABACBAY 301201101001 DAADAADAADAAY 112 3210 301201101001 ABDDBABDADBA DAADAADAADAAY ABCCBABACBAY CD 0 1 1 D CD 2 CD 3 113 BCCACBAY 114 115 ABDDCBABDACBAF 1 116 DCABDBAABDCABDBAF 2 117 ABDDCBABDACBAF 1 DCABDBAABDCABDBAF 2 CD 0 1DD 1 1DCD 2 1DD 3 1 02 0 D02 1 DDD 2 2DCD 3 2 118 CD 0 1DD 1 1DCD 2 1DD 3 1 02 0 D02 1 DDD 2 2DCD 3 2 119 120 4.4 4.4 组合逻辑电路的险象组合逻辑电路的险象 4.4.1 4.4.1 竞争竞争(Race)(Race) 121 4.4.2 4.4.2 冒