1. Mux 2.1 Multiplexers and De-Multiplexers 2: ©Paul Godin Updated November 2007

2. Mux 2.2 De-Multiplexers ◊De-Multiplexers are often used in conjunction with other digital circuits such as decoders, counters and other multi-function devices.

3. Mux 2.3 A simple De-MUX X Y S A Selects whether input “A” goes to “X” or “Y”

4. Mux 2.4 A Simple De-Multiplexer (2-output) S Z B A B A If S = 1, value Z is forwarded to A If S = 0, value Z is forwarded to B Boolean Expression: A = SZ Boolean Expression: B = S’Z

5. Mux 2.5 A 1-to-4 De-Multiplexer S0S0 S1S1 Z B C D A B A C D Build a function table for this circuit

6. Mux 2.6 A multi-channel De-MUX a1 b1 c1 d1 S A B C D a2 b2 c2 d2 Channel 1 Channel 2

7. Mux 2.7 Address De-Multiplexer ◊Microprocessors often multiplex their address bus with their data bus. This is to save on pins and physical size. ◊At times, address information is on the bus and at other times data is on the bus. μPμP

8. Mux 2.8 Address De-Multiplexer The Control output from the microprocessor indicates whether the bus is in Address mode or in Data mode. ADDRESS DATA Control AD Bus Memory μPμP

9. Mux 2.9 Questions ◊What is the difference between a de-multiplexer and an encoder?

10. Mux 2.10 Questions ◊Identify the following as MUX or De-MUX From Texas Instruments, Specification sheet for SN74LS194

11. Mux 2.11 Questions ◊Identify the following as MUX or De-MUX From Texas Instruments, Specification sheet for CD74AC139

12. Mux 2.12 End prgodin @ gmail.com