清华阎石《数字电子技术基础》教学ppt课件第四章.ppt

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1、组合逻辑组合逻辑 电路电路1a2ana1y2ymy组合逻辑电路的框图组合逻辑电路的框图)(AFY ）aa(afy)aa(afy)aa(afynmmnn2121222111如果信号灯如果信号灯出现故障，出现故障，Z为为1RAGZRAGRAGGRAAGRGARZAGRGRAGARZ012345670123456701234567012345672IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIY753107632176542IIIIYIIIIYIIIIY45675676772IIIIIIIIIIY45672IIIIYBABAA低电平)()()(SIIIIIIIIIIYSIIIIII

2、IIYSIIIIY6421643567054234567145672)(45672IIIIY选通信号)(SIIIIY45672)()()(SIIIIIIIISSIIIIIIIIYSIIIIIIIIYEXS012345670123456701234567为0时，电路工作无编码输入为0时，电路工作有编码输入76543210IIIIIIIIS012YYYEXSYYEXSYY15A0EXY815AA19II9I0IEXY70127201221012100120mAAAYmAAAYmAAAYmAAAY.用二极管与门阵列组成的3线8线译码器低电平输出附加控制端123SSSS )(iimSY 32SS 01

3、234567YYYYYYYYiimZ D3=1D3=0)(90imYiiimYABCCBBCAZCABBAZCBABCZCABBCAACZ4321),(),(),(),(742053273165434321mABCCBBCAZmCABBAZmCBABCZmCABBCAACZ)(),()(),()(),()(),(74204532373126543174205327316543mmmmmZmmmmZmmmmZmmmmmZ)()()()()()()(0121230112023012012012012012230120121302130123AAAAAAYAAAAAAAYAAAYAAAAAAAAAY

4、AAAAAYAAAAAAAAYAAAAAAAAYgfedcbaLT当 时，Ya Yg全部置为10LTRBI当 时， 时，则灭灯0RBI00000123AAAARBOBI0BI00123AAAA0RBIRBO0RBORBIRBORBORBIRBORBI)()()()(01301201101011AADAADAADAADSY1S70126012501240123012201210120012DAAADAAADAAADAAADAAADAAADAAADAAAY)()()()()()()()(位地址输入端作为第利用3S)()()()(0130120110101AADAADAADAADY)()()()(A

5、GAGRGARGARRAGRAGGRAAGRGARZ1)()()()(01301201101011AADAADAADAADSYABCOBAS)()(CIACIBBACOABCICIABCIBACIBASiiiiiiiiiiiiCIBABACOCIBASCOCI)()()()()(1)()()()()()()()()()()()(:)()()()()()()()(:)()()()(:0000011112222220000011112222222222000001111120000011110111110000011011101000000000002100CIBABABABABACIBASCIB

6、ABABABABABACIBABACOCIBABABABACOCIiCIBABABABACOBABACOCIBABABACOBASCOCIiCIBABACOCIBASCIi00110123 DCBAYYYY？D2D1D0)()()()(),(,),(,),(BAYBABABAYBABABAABYABBABABABABA10110101或同为则则)()()()()()()()()()()()()()()()(BABABABABAYYYBABABABAYBABABABABABABABABABAYBBBBAAAA001122330011223311223322333301230123和比较为附加端，用于扩展和)()()(,BABABAIII输出允许信号来自低位的比较结果来自低位的比较结果BAIIIBABABA,)()()(冲。输出端可能产生尖峰脉和所以或在动态过程中可能出现时，从当0311000110YYAB冒险改变状态时存在竞争当稳态下的条件下，在AYAAYCBCAABY11BCCAABY