Lecture 8 Transistors and CMOS Topics Combinational Circuits Quiz Structural VHDL Lab 2 VHDL: Decoders, Multiplexers Demultiplexers Readings 3. September 25, 2003 CSCE 211 Digital Design

– 2 – CSCE 211H Fall 2003 Overview Last Time Lab 3 – VHDL Lab 3 Deliverables:New Encoders/Priority Encoders Transistors CMOS gates Review for testHistory Invention of transistor

– 3 – CSCE 211H Fall 2003 Honors College: Advisement Appointment Sign-up begins Wednesday October 1 8:00AM Outside main office 2 nd floor Harper Advisement begins Monday October 6 CSCE Classes (lower level) CSCE 145 MW 2:30-3:45 Fuchs CSCE 146 TTH 9:30-10:45 Bowles CSCE 212H TTH 12:30-1:45 Matthews CSCE 240MWF 9:05-9:55 Fuchs CSCE 245MW 4:00-5:15

– 4 – CSCE 211H Fall 2003 Lab 3 Deliverables  VHDL for 74LS47’ where the ’ means don’t care for 10 … 15 using functions given in class (slide )  Schematic using components (symbols) made for 74LS47 and 74LS153 (Mux). Add output ports to outputs of 74LS47 and label them with the pin numbers for your seven segment display digit. The input ports should also be labeled.  Circuit for selecting one base-4 number with a mux and displaying it on the even segment display. You must use the DIP switch to set the input of four base-4 numbers. The select line inputs will be just wires.

– 5 – CSCE 211H Fall 2003 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.

– 6 – CSCE 211H Fall 2003 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) (aj) c <= a or not b or d (david) d = e = A(bar) and (B or C(bar)) (jeremy/patrick) f = D + A'B' + B'C + A'BC (jon) g=D + B'C + C'B + A'B (msbell)

– 7 – CSCE 211H Fall 2003 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( ) BA DC A D C B period(D,C,B,A) =

– 8 – CSCE 211H Fall 2003 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 Timelinehttp://

– 9 – CSCE 211H Fall 2003 Transistor: Water Flow Model Water flow in B raises the plunger so that water can flow from C to E. Small flow turns on and off bigger flow. Put signal on B, transfer signal C to E Reference:

– 10 – CSCE 211H Fall 2003 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)

– 11 – CSCE 211H Fall 2003 Transistor Reference:

– 12 – CSCE 211H Fall 2003 Transistor Reference:

– 13 – CSCE 211H Fall 2003 Transistor Reference: Put Positive charge on gate. This attracts electrons into gap. This allows electrons to pass freely through the gap.

– 14 – CSCE 211H Fall 2003 Transistor Reference:

– 15 – CSCE 211H Fall 2003 Transistor Reference: Take positive charge off Gate This stops attracting electrons. This shuts off the flow.

– 16 – CSCE 211H Fall 2003 N channel transitor

– 17 – CSCE 211H Fall 2003 P channel Transistor

– 18 – CSCE 211H Fall 2003 CMOS Inverter

– 19 – CSCE 211H Fall 2003 CMOS NAND

– 20 – CSCE 211H Fall 2003 What’s This?

– 21 – CSCE 211H Fall 2003 Test / Sample Test