09 - MSI elements - 30-Jan-069:54 AM11University of...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 30-Jan-069:54 AM11University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoMSI ElementsEEL 37011University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701Menu MSI elements>Decoders (pages 2-8)>Encoders (page 9)>Multiplexers (pages 10-11, 13-18)>DeMux (page 12)>Open collector gates (pages 19-25)>Tri-state Buffers (pages 26-30)Look into my ...See Lam Figures from chapter 4EEL 37012University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 37013-to-8 Decoder(3 input to 8 output; binary to singulary #)DecoderLook at Z= /A2/A1/ALook at Z1= /A2/A1AZZ73-to-8 DecoderA2A1AZ-Z7Z1A2(H)A1(H)A(H)Z(H)A2(L)A1(L)A(L)A2(L)A1(L)A(H)Z1(H)What is the equation of Z6? ____________Draw the circuit.30-Jan-069:54 AM22University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoMSI ElementsEEL 37013University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701Unit VectorsDecoder> If X1X=00, Z=1, Z1=Z2=Z3=0, i.e., Z3Z2Z1Z=0001 = u> 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 = u3 A decoderis a circuit that performs the following logic:DecoderX1XZZ1Z2Z3A1AYY1Y2Y3EEL 37014University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701Decoder with Enable>If E=1, then Zi=1 and all other Zs=0 One selected>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 A decoderwith an enable, E, performs the following logic:DecoderX1XZZ1Z2Z3EA1AEYY1Y2Y330-Jan-069:54 AM33University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoMSI ElementsEEL 37015University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701 Decoders are useful because quite often information is encoded Why?Decoder: Why? What is an enable input? Why do we need it?>Added to: (1) Keep the circuit out of the way when not needed (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.DecoderX1XZZ1Z2Z3EA1AEYY1Y2Y3EEL 37016University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701Decoder ExpansionNOTE:We can build 3-to-8, 4-to-16, 5-to-32 decoders using 2-to-4s.NOTE:We can build 4-to-16, 5-to-32 decoders using 74138s. Make a 3-to-8 decoder with two2-to-4 decodersSee Lam: Fig. 4.9, 4.10, 4.11X2(L)X2(H)2-to-4DecoderZ(H)Z1(H)Z2(H)Z3(H)X2(L)A1AEYY1Y2Y32-to-4DecoderX1(H)X(H)X2(H)A1AEYY1Y2Y3Z4(H)Z5(H)Z6(H)Z7(H)X1(H)X(H) Can you do this and keep an enable on the new 3-to-8 decoder?30-Jan-069:54 AM44University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoMSI ElementsEEL 37017University of Florida, EEL 3701 File 09 Drs. Schwartz & ArroyoEEL 3701 BCD = Digits 0~9; Y3Y2Y1Y= 0000, 0001, ..., 1001= 0000, 0001, ....
View Full Document

Page1 / 17

09 - MSI elements - 30-Jan-069:54 AM11University of...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online