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SYEN 3330 Digital Systems. Chapter 4 -Part 1. Functional Block: Decoders. 2-to-4 Line Decoder. 2-to-4 Line Demultiplexer. Example: 74F138 Demultiplexer. Note: This "Truth Table" uses the "x" to mean "this could be either 0 or 1". Thus, it "compacts" some of 2 6 = 64 lines.
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SYEN 3330 Digital Systems Chapter 4 -Part 1 SYEN 3330 Digital Systems
Functional Block: Decoders SYEN 3330 Digital Systems
2-to-4 Line Decoder SYEN 3330 Digital Systems
2-to-4 Line Demultiplexer SYEN 3330 Digital Systems
Example: 74F138 Demultiplexer Note: This "Truth Table" uses the "x" to mean "this could be either 0 or 1". Thus, it "compacts" some of 26=64 lines. SYEN 3330 Digital Systems
Implementing Logic with Decoders SYEN 3330 Digital Systems
m3 F m0 A B Example 1:F(A,B) = m(0,3) SYEN 3330 Digital Systems
Example 1:F(X,Y,Z) = m(0,3,5,6) SYEN 3330 Digital Systems
D3 m15 D2 A D1 S1 m?? D0 B S0 D3 D2 C D1 S1 m0 D0 D S0 Implementing Larger Minterms SYEN 3330 Digital Systems
Functional Block: Encoders SYEN 3330 Digital Systems
Review: Decoders and Encoders SYEN 3330 Digital Systems
Multiplexers SYEN 3330 Digital Systems
I3 I2 X I1 I0 S1 S0 Example: A 4-to-1 multiplexer SYEN 3330 Digital Systems
I3 I2 X I1 I0 S1 S0 Multiplexer Versus Decoder Note how similar the two are internally. SYEN 3330 Digital Systems
Functions with Multiplexers SYEN 3330 Digital Systems
Example: Gray to Binary Code SYEN 3330 Digital Systems
Gray to Binary (Continued) SYEN 3330 Digital Systems
Gray to Binary (Continued) SYEN 3330 Digital Systems
0 1 D7 D7 1 0 D6 D6 1 0 D5 D5 0 1 D4 D4 Y Z 0 D3 D3 0 Out Out 1 1 D2 D2 1 1 D1 D1 0 0 D0 D0 A A S2 S2 8-to-1 8-to-1 B S1 S1 B MUX MUX S0 S0 C C Gray to Binary (Continued) SYEN 3330 Digital Systems
Other MUX Implementations B Y 00 01 11 10 B Z 00 01 11 10 0 1 0 1 0 1 0 1 D0 D1 D3 D2 D0 D1 D3 D2 A 1 0 1 0 A 0 0 1 1 C C A A A A SYEN 3330 Digital Systems
0 D3 D3 A 1 A' D2 D2 Y Z 1 A' D1 Out D1 Out A 0 D0 D0 4-to-1 4-to-1 S1 B S1 B MUX MUX S0 S0 C C MUX Implementations (Cont.) SYEN 3330 Digital Systems
MUX: (Cont.) Factoring Out C SYEN 3330 Digital Systems
MUX: (Cont.) Factoring out B SYEN 3330 Digital Systems
MUX: (Cont.) Factoring out A SYEN 3330 Digital Systems
Summary • Know the functions performed by the following functional blocks: • Decoders • Demultiplexers • Encoders • Multiplexers • Know how to implement Boolean functions using: • Multiplexers • Decoders SYEN 3330 Digital Systems