# 09 - 14-Sep-1011:31 AMMSI Elements1University of Florida,...

This preview shows pages 1–4. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 14-Sep-1011:31 AMMSI Elements1University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701EEL 3701Menu MSI elements>Decoders (pages 2-11)>Encoders (page 12)>Multiplexers (pages 15-17, 19-25)>DeMux (page 18)>Open collector gates (pages 25-32)Look into my ...1University of Florida, EEL 3701 File 09 Drs. Schwartz & Arroyo>Tri-state Buffers (pages 33-37)See Lam Figures from chapter 4EEL 3701EEL 37013-to-8 Decoder(3 input to 8 output; binary to singulary #)DecoderZA2Z1Look at Z= /A2/A1/ALook at Z1= /A2/A1AZ73-to-8 Decoder2A1AZ-Z71A2(H)A2(L)A2(L)Z (H2University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoA1(H)A(H)Z(H)A1(L)A(L)A1(L)A(H)Z1(H)What is the equation of Z6? ____________Draw the circuit.14-Sep-1011:31 AMMSI Elements2University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701EEL 3701Decoder A decoderis a circuit that performs the following Unit Vectors> If X1X=00, Z=1, Z1=Z2=Z3=0, i.e., Z3Z2Z1Z=0001 = ulogic:DecoderX1(H)X(H)Z(H)Z1(H)Z2(H)Z3(H)A1AYY1Y2Y33University of Florida, EEL 3701 File 09 Drs. Schwartz & Arroyo> If X1X=01, Z1=1, Z=Z2=Z3=0, i.e., Z3Z2Z1Z=0010 = u1> If X1X=10, Z2=1, Z=Z1=Z3=0, i.e., Z3Z2Z1Z=0100 = u2> If X1X=11, Z3=1, Z=Z1=Z2=0, i.e., Z3Z2Z1Z=1000 = u3EEL 3701EEL 3701Decoder with Enable A decoderwith an enable, E, performs the following logic>If E=1, then Zi=1 and all other Zs=0 One selectedfollowing logic:DecoderA1AEYY1Y2Y3X1(H)X(H)E(H)Z(H)Z1(H)Z2(H)Z3(H)4University of Florida, EEL 3701 File 09 Drs. Schwartz & Arroyo>If E=0, the all Zs=0 None selected>Thus, when E=1 and X1X=102=2, Z2=1, Z=Z1=Z3=0. >A decoder (when enabled) decodes a binary word In this example, a two bitbinary word 14-Sep-1011:31 AMMSI Elements3University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701EEL 3701 Decoders are useful because Decoder: Why?DecoderA1AEYY1Y2Y3X1(H)X(H)E(H)Z(H)Z1(H)Z2(H)Z3(H)quite often information is encoded Why? What is an enable input? Why do we need it?>Added to: (1) Keep the circuit out of the way when not needed5University of Florida, EEL 3701 File 09 Drs. Schwartz & Arroyo (2) Because in a true singulary representation all zeros are not allowed. Thus, all zis 0 is not legal (by definition).>The IC works if Enable = 1, else chip is out of the circuit.EEL 3701EEL 3701Decoder Expansion Make a 3-to-8 decoder with two2 t4 ddX2(L)X2(H)Z(H)AYX1(H)3-to-8 DecoderZ(H)Z1(H)Z2(H)YY1Y2X2(H)A2-to-4 decoders2-to-4DecoderZ1(H)Z2(H)Z3(H)X2(L)A1AEY1Y2Y32-to-4DecoderX1(H)X(H)X2(H)A1AEYY1Y2YZ4(H)Z5(H)Z6(H)Z (H1X(H)X1(H)X(H)Z3(H)A1AY322Z4(H)Z5(H)Z6(H)Z7(H)Y4Y5Y6Y7 Can you do this and keep an enable on the new 3-to-8 decoder?Do itE(H)EFunctional Block Diagram6University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoNOTE:We can build 3-to-8, 4-to-16, 5-to-32 decoders using 2-to-4s....
View Full Document

## This note was uploaded on 01/06/2011 for the course EEL 3701c taught by Professor Gugel during the Spring '05 term at University of Florida.

### Page1 / 20

09 - 14-Sep-1011:31 AMMSI Elements1University of Florida,...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online