Microcomputers

Microcomputer Microcontroller What’s the difference? Microcomputer Microcontroller

Homework 7 What is a microcontroller? What are some common applications of these? A microcontroller is a simple computer on a single silicon chip that cost only a few dollars. They are useful in washing machines, toasters, and cars.

Microcontrollers in Cars and Trucks? All modern automobiles contain at least one microcontroller, and can have as many as six or seven. The engine is controlled by a microcontroller, as are the anti-lock brakes, the cruise control and so on.

Interesting… Any device that has a remote control almost certainly contains a microcontroller: TVs, VCRs and high-end stereo systems all fall into this category. Digital cameras, cell phones, camcorders, answering machines, laser printers, telephones (the ones with caller ID, 20-number memory, etc.), pagers, and feature-laden refrigerators, dishwashers, washers and dryers. Basically, any product or device that interacts with its user has a microcontroller buried inside.

PIC Microcontroller We will use the 16F84A microcontroller made by Microchip for the team project. Use the Internet to research these chips.

Acronyms IC RAM ROM PROM EPROM EEPROM PIC

IC – Integrated Circuits

RAM – Random Access Memory

ROM – Read Only Memory ROM cannot be modified (at least not very quickly or easily),

ROM – Read Only Memory ROM cannot be modified (at least not very quickly or easily),

PROM – Programmable Read Only Memory setting of each bit is locked by a fuse

PROM The voltage breaks the connection between the column and row by burning out tiny fuses. PROMs can only be programmed once.

Google “PROM Memory”

EPROM – Erasable Programmable Read Only Memory

EEPROM – Electronically Erasable Programmable Read Only Memory

EEPROM – Electronically Erasable Programmable Read Only Memory

PIC – Programmable Integrated Circuits

What is RAM? List two types. RAM = random access memory Read-and-Write Memory volatile Types Static RAM - on flip-flops Dynamic RAM - with transistors and capacitors

4. What is ROM? List four types. ROM = read only memory nonvolatile (retaining data when powered down) permanent Types mask-programming ROM written when manufactured PROM - programmable read-only memory blow tiny fuses EPROM - erasable PROM by UV light EEPROM - electrically erasable PROM 16F84A

EPROM Erasing an EPROM requires a special tool that emits a certain frequency of ultraviolet (UV) light.

EEPROM These are programmed and erased electronically. These are the kind that we will use for the rovers.

List three examples of mass-storage devices. Hard Disk Floppy Disk Digital Tape CD-ROM

Which type of memory is least expensive per using storage Which type of memory is least expensive per using storage? RAM, ROM, or Mass-Storage? Mass-Storage

Classify each of these as RAM, ROM, Mass-Storage. Hard Disk Boot programs are stored here. CD-ROM A SIMM or a DIMM for your computer are examples of this. http://www.webopedia.com Floppy Disk Clothes washer cycle program is stored here.

8. What does A/D and D/A mean? A/D = Analog to Digital Converters D/A = Digital to Analog Converters

9. Are multimeters A/D or D/A devices? Multimeters have A/D converters. What’s a good example of an D/A converter?

The SFA Rover Team Project

A Robot with a Brain Each vehicle will have a programmable integrated circuit (PIC) that will make decision and control the motors automatically. This kind of robot control is the same kind of control that is used on Mars robot rovers.

The Vehicle Course 6-feet 50-feet

The Vehicle Course 6-feet 50-feet Extra Credit

Scoring D = Distance traveled in feet in 10 minutes (the maximum distance is 50-feet) R = 15 if the vehicle successfully demonstrates avoiding an obstacle on the right and 0 if it is not demonstrated L = 15 if the vehicle successfully demonstrates avoiding an obstacle on the left and 0 if it is not demonstrated T = -10 each time the vehicle is touched by a team member during the course Grade = T + L + R + D × 70/(50ft) Bonus: For each extra left or right obstacle avoided, 2 points of extra credit will be earned for each member of the team. A maximum of 20 extra points can be earned in this manner.

SFA Rover Circuit Diagram Left Button Right Button 9-Volt Battery PIC Microcontroller Voltage Regulator H-Bridge Left Motor Right Motor

Key Concepts Note that the parts used in the team project are discussed in your text book. Chapter 7 - Logic Circuits Chapter 8 - Microcomputers Chapter 10 - Diodes (Voltage Regulator) Chapter 12 - Transistors (H-Bridge) Chapter 16 - DC Machines (Motors)

Key Concepts Other key ideas used in this team project include: Battery Power Management Torque Friction Gearboxes We will now design circuits that will be used in lab next week.

More Construction Now use the parts provided to construct a chassis for your vehicle. If time permits, move you H-Bridge to a portable breadboard and power it using a voltage regulator and 9-Volt battery. If you are successful, then try to run your vehicle straight down the course.

To be continued… If you did not complete the course, then use some lab time this week to modify your vehicle until it can complete the 50-foot course. We will integrate the PIC microcontroller and buttons into the circuit later. This will allow the vehicles to avoid obstacles.

Beginning the Construction There should be 3-4 members on each team. Two team members will now work on together on one Heathkit Digital Experimenter. In pairs take one motor and connect it between 0 and 5 Volts. Reverse the wires and notice that the motor rotates in the opposite direction.

Beginning the Construction Turn off the power. Now connect the motors to the H-Bridge chip. Use two Data Switches as inputs into the H-Bridge that can be used to change the direction of the motors. * Make notes about your wiring so that you can reconstruct this circuit on a portable breadboard later.

Chapter 10 Diodes

Semiconductors Germanium Silicon 32 protons 14 protons Most commonly used

Atomic Physics How many electrons can be in the ground state of an atom? Answer: 2 (s level) ...in the first excited state? Answer: 8 (s and p levels) …in the second excited state?

Valence Electrons Valence electrons are electrons in the outermost shell of the atom that can participate in forming chemical bonds with other atoms. How many valence electrons does Silicon have? Answer: 4

How many electrons are needed to fill the outermost energy level of Silicon? Answer: 4 2-D representation of Silicon Crystal How many valence electrons does Phosphorus (15P) and Aluminum (13Al) have? Answers: 5 and 3

Diodes Conduct electricity in one direction Two terminal devices anode and cathode Primarily made of silicon

Doping The adding of impurities n-type crystal e.g. Silicon doped with Phosphorous negative charge carriers electrons p-type crystal e.g. Silicon doped with Aluminum positive charge carriers vacancy or hole

Diodes Circuit Symbol p-type n-type

Flapper Valve Analogy Flapper Valve Analogy

Diode Characteristics Forward-Bias Condition Good Conductor Reverse-Bias Condition High Resistance I versus V Plot Ideal Diode and Real Diode “Knee” and Breakdown Voltage Three Regions

Shockley Equation Shockley Equation on Excel Common LED have a maximum recommended current of 20mA. What resistor value is needed in series with an LED and a 5-Volt power supply so that the LED does not burn up? Answer: _______ or ________

What does the circuit symbol for an LED look like?

Diode Circuits rec·ti·fi·er Pronunciation: 'rek-t&-"fI(-&)r Function: noun Date: 1611 : one that rectifies; specifically : a device for converting alternating current into direct current Half-Wave Rectifier Full-Wave Rectifier Bridge Rectifier

Smoothing Capacitors Ripple Voltage (Vr) DC Component (VDC) Ripple Factor

Concept Test Is a high or low value for the ripple voltage DV desirable? Answer: Low What are three ways to achieve low ripple voltages? Answers: Low Current High Frequency High Capacitance

Zener Diodes Zener Diodes are intended to operate in the breakdown region. Manufacturers set the breakdown voltage by modifying the doping. Zener diodes can make good voltage regulators. Circuit Symbol Clarence Zener once visited SFA.

What is a Zener diode? How do the circuit symbols for a diode and a Zener diode differ? Zener diodes are intended to operate in the breakdown region -usually as voltage regulators. Manufacturers set the breakdown voltage by careful doping.

How do you convert AC to DC? AC Input Diode Rectifier Smoothing Capacitor DC Output Voltage Regulator Voltage Regulators remove the ripple.

Concept Question What components to you need to convert a 110-Volt AC signal to a 9-Volt DC signal? Answers: Transformer – to step down the voltage Diodes – to rectify the waveform (make +) Capacitor – to smooth the rectified waveform Voltage Regulator – to remove the ripple Note that the device connected to this 9-Volt power supply acts as a resistor. For this reason the device is sometimes called the “load” or “load resistance”.

Example Questions 10.32, 35 Homework Questions? 10.55, 56, 57, 35

What is an ideal diode? An ideal diode is a perfect conductor with zero voltage drop in the forward bias direction… …and a perfect insulator in the reverse bias direction.

Stop Here

What element from the periodic table are diodes made of? Silicon