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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1. Lecture 7 Combinational Components II Topics
Components on integrated circuit (ICs)
Readings 5.4, 5.7
2. Overview Last Time:
Sums-of-Products Form Pop Quiz
Definition of Combinational Circuit (feedback loop)
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
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?
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.
Current HDLs include:
VHDL – VHSIC HDL
VHSIC – Very High Speed Integrated Circuits
ABEL HDL - Advanced Boolean Expression Language
21. VHDL Elements Identifiers – much like C or Java, L(L| _ | D)*
Entity – like an interface
Architecture – specification of what the circuit does
22. VHDL Half Adder Entity entity HALFADDER is port( A, B: in bit; SUM, CARRY: out bit); end HALFADDER;
in – inputs to the circuit
out – outputs from the circuit
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;
entity mux4in18b is
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
26. VHDL MUX Architecture architecture mux4in18p of mux4in18b is
process(S, A, B, C, D)
variable i: INTEGER;
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');
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)
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.
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
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)
39. N channel transitor
40. P channel Transistor
41. CMOS Inverter
42. CMOS NAND
43. What’s This?