《数字电》英文版 chapter3-1 Combinational logic Circuits

Combinational logic Circuits Chapter 3 Integrated Digital Circuit

Combinational logic circuits Chapter 3 Integrated Digital Circuit

INTRODUCTION Level five Complex Systems, Function Units from levels Two through Four evel four More complex Function Logic Units, e.g. Third Ic level(VLSI) microprocessor d three Function Logic Units, e.g. adders, Second ic level counters, multiplexers (MSI and LSI) Level two Function Logic Units, e.g. gates, NOT AND NAND, EX-OR First IC level (SSI) Level one Electronic Components,e.g. transistors, Components level diodes, resistors, capacitors

INTRODUCTION Components level First IC level (SSI) Level four Level three Level five Electronic Components, e.g. transistors, diodes, resistors, capacitors Function Logic Units, e.g. gates, NOT, AND, NAND, EX-OR Function Logic Units, e.g. adders, counters, multiplexers More complex Function Logic Units, e.g. microprocessor Complex Systems, Function Units from levels Two through Four Third IC level (VLSI) Second IC level (MSI and LSI) Level two Level one

INTRODUCTION a The most common transistor-transistor logic (TTL) a emitter-coupled logic(ECL) a complementary metal-oxide semiconductor logic(CMOS a Each of these main logic families is made up of numerous subfamilies

INTRODUCTION  The most common ◼ transistor-transistor logic (TTL) ◼ emitter-coupled logic (ECL) ◼ complementary metal-oxide semiconductor logic (CMOS).  Each of these main logic families is made up of numerous subfamilies

INTRODUCTION SN54/74ALSOO SN is a prefix. The prefix indicates the manufacturer the number 54 indicates a military operating temperature range and 74 indicate a commercial temperature range both temperature ranges are available for most functions and subfamilies the letter-number combination following the sn54/74 indicates the subfamily and the logical function of the IC SN74ALSOo is a commercial temperature range advanced low-power schottky Nand gate IC manufactured by Texas instruments

INTRODUCTION  SN54/74ALS00 ◼ SN is a prefix. The prefix indicates the manufacturer. ◼ The number 54 indicates a military operating temperature range and 74 indicate a commercial temperature range. Both temperature ranges are available for most functions and subfamilies. ◼ The letter-number combination following the SN54/74 indicates the subfamily and the logical function of the IC. ◼ SN74ALS00 is a commercial temperature range advanced low-power schottky NAND gate IC manufactured by Texas instruments

Decoder a Decoder convert a set of input variables representing a code into a set of variables representing a different code. The relationship between the input and output codes can be expressed in a truth table a Encoded information is presented as n inputs producing 2n outputs. The outputs values can range from 0 to 2n-1 a Some decoder generate outputs over a truncated portion of possible values

Decoder  Decoder convert a set of input variables representing a code into a set of variables representing a different code. The relationship between the input and output codes can be expressed in a truth table.  Encoded information is presented as n inputs producing 2n outputs. The outputs values can range from 0 to 2n -1.  Some decoder generate outputs over a truncated portion of possible values

Decoder n-data Inputs possible outputs Enable Inputs ypIcal ecoder

Decoder Typical decoder Enable inputs n-data inputs 2 n possible outputs

D ecoder a Decoder can be used as minterm or maxterm generators 口TT74x×138 3-t0-8 decoder multiple 3-to -8 decoders can be cascaded to form 4-to-16 or even large decoders

Decoder  Decoder can be used as minterm or maxterm generators.  TTL74xx138 ◼ 3-to-8 decoder ◼ multiple 3-to -8 decoders can be cascaded to form 4-to-16 or even large decoders

D ecoder 口F(A,B,C) =TM(0,1,2,4,7) ABc YO Y1 口F(A,BC) Y2 =∑m(2457 Y3 Y4 >To 74LS138 G1 Y5 G2A Y6 yi corresponds to Maxterm i G2B Y7 yⅰ=Mi 74Ls138

Decoder  F(A,B,C) =∏M(0,1,2,4,7);  F(A,B,C) =∑m(2,4,5,7); A B C G1 G2A’ G2B’ Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 74LS138 ►To 74LS138 ►Yi corresponds to Maxterm i. ►Yi=Mi

D ecoder 口F(A,BC)=TM(0,1,2,4,7 ABc YO ABc F Y1 Y2 Y3 o Y4 G1 YaO 0-- G2A Y6O 0_G2B Y7 74Ls138

Decoder  F(A,B,C) =∏M(0,1,2,4,7); A B C G1 G2A’ G2B’ Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 74LS138 F A B C 1 0 0

D ecoder 口F(A,BC)=zm(245,7)TM(0,1,36) YO F Bc ABc Y2 Y3 Y4 P G1 Y5 o 0--G2A Y6 G2B Y7 74Ls138

Decoder  F(A,B,C) =∑m(2,4,5,7)=∏M(0,1,3,6); A B C G1 G2A’ G2B’ Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 74LS138 F A B C 1 0 0