Lecture 7 Combinational Components II

Lecture 7 Combinational Components II PowerPoint PPT Presentation


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Overview. Last Time:Sums-of-Products Form Pop QuizProducts-of-Sums FormDefinition of Combinational Circuit (feedback loop)New:From Lecture 6 slidesDecoders 2x4, 3x8 from 2x4'sMultiplexers: in general selects input to pass to outputMultiplexers: 4-to-1 MUXBig Mux from little muxes5 and 6 v

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Lecture 7 Combinational Components II

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1. Lecture 7 Combinational Components II Topics Combinational Circuits Decoders Multiplexers Breadboards, LEDs Components on integrated circuit (ICs) Readings 5.4, 5.7

2. Overview Last Time: Sums-of-Products Form Pop Quiz Products-of-Sums Form Definition of Combinational Circuit (feedback loop) New: From Lecture 6 slides Decoders 2x4, 3x8 from 2x4’s Multiplexers: in general selects input to pass to output Multiplexers: 4-to-1 MUX Big Mux from little muxes 5 and 6 variable Karnaugh maps

3. Homework Update HW - 4 4.15c products of sums not what the text says 4.59a 5-variable map Old Test1 on website ???

4. 6 Variable Map F(U,V,W,X,Y,Z) =

5. Analyze This!

6. Quick What’s This?

7. What’s This?

8. 8 to 1 Mux from 4x1 Muxes

9. Big Multiplexers from smaller ones Show the design of a 32-to-1 Mux from 8-to-1’s and smaller muxes

10. BreadBoard

11. Wiring an LED

12. 74LS00 – Quad 2 input NAND

13. 74LS04 Hex Inverter

14. Two Bit adder How many inputs? How many outputs? Do we have enough chips?

15. BreadBoard

16. Implementing a Binary Adder Using a Decoder

17. 74LS139 Decoder Dual 2x4 decoder

18. Using a 74LS139 to implement a Half-adder

19. 74LS157 Dual 4 input Mux

20. Hardware Description Languages Hardware description language or HDL is any language from a class of computer languages for formal description of electronic circuits Boolean Algebra was applied to circuits by Shannon 1948. http://cm.bell-labs.com/cm/ms/what/shannonday/paper.html Current HDLs include: Verilog HDL VHDL – VHSIC HDL VHSIC – Very High Speed Integrated Circuits ABEL HDL - Advanced Boolean Expression Language http://en.wikipedia.org/wiki/Hardware_description_language

21. VHDL Elements Identifiers – much like C or Java, L(L| _ | D)* Entity – like an interface Architecture – specification of what the circuit does Behavioral description Structural description

22. VHDL Half Adder Entity entity HALFADDER is    port(       A, B:                in   bit;       SUM, CARRY: out bit); end HALFADDER; Interface description Ports in – inputs to the circuit out – outputs from the circuit in out No behavior described

23. VHDL Half Adder Architecture entity HALFADDER is    port(       A, B:                in   bit;       SUM, CARRY: out bit); end HALFADDER; architecture RTL of HALFADDER is begin    SUM      <= A xor B;    CARRY <= A and B; end RTL; -- VHDL'93: end architecture RTL ;

24. VHDL Compilation

25. VHDL MUX library IEEE; use IEEE.std_logic_1164.all; entity mux4in18b is port ( S: in STD_LOGIC_VECTOR (2 downto 0); -- Select inputs, 0-7 ==> ABACADAB A, B, C, D: in STD_LOGIC_VECTOR (1 to 18); -- Data bus inputs Y: out STD_LOGIC_VECTOR (1 to 18) -- Data bus output ); end mux4in18b;

26. VHDL MUX Architecture architecture mux4in18p of mux4in18b is begin process(S, A, B, C, D) variable i: INTEGER; begin case S is when "000" | "010" | "100" | "110" => Y <= A; when "001" | "111" => Y <= B; when "011" => Y <= C; when "101" => Y <= D; when others => Y <= (others => 'U'); end case; end process; end mux4in18p;

27. Seven Segment Display Common anode

28. Functions for 74LS47 with don’t cares a(D,C,B,A) = D + A.C + A.B + A’.C’ b(D,C,B,A) = D + (D'*C') + (A'*B') + (A*B) c <= d = e = A(bar) and (B or C(bar)) f = D + A'B' + B'C + A'BC g=D + B'C + C'B + A'B

29. Karnaugh Map Simplification On a real 74LS47 the outputs for 10, …15 are not don’t cares. They would indicate errors in BCD input. We could use the period for that. period(D,C,B,A)=SUM( ) dc(D,C,B,A) = SUM( )

30. Transistors History 1790s Ben Franklin “assigns” negative charge to electrons 1898 Thompson discovers the electron 1947 Shockley, Bardeen and Brattain “invent” transistor 1958 first Integrated Circuit, Texas Instruments 1971 Intel 4004, microprocessor, Ted Hoff Timeline http://www.pbs.org/transistor/

31. Hot Batteries You should regularly check your batteries “slightly warm” is OK but hot indicates that your circuit has a short circuit. Unplug quickly and check. Look for direct lines Vcc to GND. Remember you need 330 ohm resistors in series with LEDs and that includes segments of the seven segment display. Recheck sections of the breadboard.

32. Transistor: Water Flow Model

33. Transistor Terminology Conductor – electrons easily passed from one atom to next (copper every atom has loose electron) Insulator – electrons tightly tied down to atoms, no flow Semiconductor – by adding impurities (doping) can be changed to increase conductivity Silicon wafer – used for IC circuits N-type - silicon doped with boron (excess electrons) P-ype - silicon doped with phosphorous (excess “holes” lack of electrons)

34. Transistor

35. Transistor

36. Transistor

37. Transistor

38. Transistor

39. N channel transitor

40. P channel Transistor

41. CMOS Inverter

42. CMOS NAND

43. What’s This?

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