Computer Engineering 360 – Microprocessors and Microcontrollers

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					       CS 150
Computer Organization &
    Architecture

        Lecture 2
                  Overview
 Quiz 2
 Topics
     Digital & Analog Systems
     Number Systems
     Codes
 New Skill:
     Dealing with ESD
   Digital And Analog Systems
 Definitions
     ANALOG
      • Values are continuously variable (on, off, or
        anything in between)
      • Examples: dimmer light switch, clock with hands
     DIGITAL
      • Values take only two forms (on or off -- nothing in
        between)
      • Examples: toggle light switch, numeric clock
    Digital and Analog Systems
Digital                           Analog
discrete steps                    continuously variable
number representations            voltages or currents
switching                         amplification/attenuation
easier to design                  real world is mainly analog
easier to store data
greater accuracy & precision
programmable
resistant to noise & component drift
smaller IC’s
                Real World System

Temperature   Measuring   Analog             Digital       Digital    Digital
                                   ADC
  (Analog)     Device                                    Processing




                          DAC      Analog   Controller           Adjust
                                                               Temperature
   Positional Number Systems
 Each symbol     has intrinsic value
     7 has more value than 3

 The position of   the symbol has value
     Example: 307
     The 3 has more value than the 7 because it
      represents 3 hundreds (3 X 102) while 7
      represents only 7 ones (7 X 100)
       Important Number Bases
 Base 2   or Binary
     Number system used by computers
 Base 10    or Decimal
     Number system used by people
 Base 16    or Hexadecimal
     Convenient shorthand for long binary
      numbers
                 Binary Numbers
BASE 10                                 BASE 2
Has 10 numeric symbols (0-9)            Has 2 numeric symbols (0-1)
Position of digit has meaning           Position of bit has meaning
Next number after 9 is 10               Next number after 1 is 10
Examples:
30510 = 300 hundreds position = 3 x 102 (MSD)
        + 00 tens position = 0 x 101
        + 5 ones position = 5 x 100 (LSD)
        305
10112 = 1000 eights position 1 x 23 (MSB)
        + 000 fours position 0 x 22
        + 10 twos position 1 x 21
        + 1 ones position 1 x 20 (LSB)
         1011
                   Hex Numbers
BASE 10                              BASE 16
Has 10 numeric symbols (0-9)         Has 16 numeric symbols (0-
                                     9,A-F)
Position of digit has meaning        Position of digit has meaning
Next number after 9 is 10            Next number after F is 10
Examples:
305d = 300 hundreds position = 3 x 102 (MSD)
        + 00 tens position = 0 x 101
          + 5 ones position = 5 x 100 (LSD)
          305
1F2Ch = 1000 fourth position 1 x 163 (MSD)
        + F00 third position F x 162
        + 20 second position 2 x 161
        + C first position C x 160 (LSD)
         1F2C
           Number Counting
Base 10:    0    Base 2:       0   Base 16: 0
            1                  1            1
            2                 10            2
            3                 11            3
            4                100            4
            5                101            5
            6                110            6
            7                111            7
            8               1000            8
            9               1001            9
           10               1010            A
           11               1011            B
           12               1100            C
           13               1101            D
           14               1110            E
           15               1111            F
           16              10000           10
          Identifying the Base
 Base 2   number
     1010b
     10102
 Base 10      number
     1010d
     101010
 Base 16      number
     1010h
     101016
 Binary to Decimal Conversion
 101011.1b =         ???d

     Multiply each digit by its position
      (1 x 23) + (0 x 22) + (1 x21) + (1 x 20) + (1 x 2-1)

     Add everything up
      = 32d + 0d + 8d + 0d + 2d + 1d + ½d

     = 43.5d
    Decimal to Binary Conversion
   213d = ???b

       Divide base 10 number by 2 and record the remainders. First
        remainder is LSB.
        213d ==>213/2 = 106 R = 1 (LSB)
                 106/2 = 53 R = 0
                 53/2 = 26 R = 1
                 26/2 = 13 R = 0
                 13/2 = 6 R = 1
                 6/2 = 3 R = 0
                 3/2 = 1 R = 1
                 1 /2 = 0 R = 1 (MSB)

     Concatenate remainders.
      11010101b
      |       |
     MSB     LSB
        Binary to Hex Conversion
   1110110111b = ???h

       Start with LSB and divide bits into groups of 4. Add
        leading zeros as needed.
                 1110110111b = 0011 1011 0111

       Convert each group of 4 bits into 1 hexadecimal digit.
               0011 1011 0111
                 3h    Bh 7h

       Concatenate hexadecimal digits for complete
        solution.
                 3B7h
      Hex to Binary Conversion
 9F =   ???b
     Convert each hexadecimal digit into its 4-bit
      binary equivalent.
            9      F
          1001b 1111b

     Concatenate binary bits for complete solution.
             10011111b
         Hex to Decimal Conversion
   BF3h = ???d
      Multiply each digit by its position
         (B x 162 ) + (F x 161 ) + (3 x 160 ) = (11 x 256) + (15 x 16) + (3 x 1)

         Add everything up
           = 2816d + 240d + 3d
           = 3059d
   OR . . .Convert hexadecimal to binary, then binary to decimal.
         BF3h = 1011 1111 0011
               = 101111110011b
               = 2048 + 512 + 256 + 128 + 64 + 32 + 16 + 2 + 1
               = 305910
         Decimal to Hex Conversion
   7213d = ???h
         Divide base 10 number by 16 and record the remainders. First
          remainder is LSB.
                  7213d ==>     7213/16 = 450 R = 13 = D (LSB)
                                450/16 = 28 R = 2
                                28/16 = 1 R = 12 = C
                                1/16 = 0 R = 1 (MSB)
        Concatenate remainders.
                1C2Dh
                 |   |
                   MSD LSD

   OR . . . Convert decimal to binary, then binary to hexadecimal.
         7213d = 11100001011012
                 = 0001 1100 0010 1101
                 = 1h    Ch 2h Dh
                 = 1C2Dh
    Binary Coded Decimal (BCD)
 Decimal numerals represented by binary bits, but the
  conversion is not a binary number.
 It is a code -- not a positional number system

Decimal
 Digit       BCD
                             Convert 249610 to BCD:
  0          0000
  1          0001              2      4       9        6
  2          0010
  3          0011            0010    0100    1001    0110
  4          0100
  5          0101
                             Note: this is very different than
  6          0110
  7          0111            converting decimal to binary
  8          1000            249610 = 1001110000002
  9          1001
 10          0001   0000
                        ASCII Code
 7-bit code for storing alphanumeric and control
  characters in computer memory
 See ASCII Table in your text or at
  http://www.AsciiTable.com
 Partial ASCII Table:



                            Example: Convert “help” to ASCII
                              h         e         l        p
                            1101000 1100101 1101100 1111000
                   Gray Code
 A binary code that changes by only 1 bit between
  successive codes.
 Used extensively for positional sensors.

2 Bit Example:     00           3 Bit Example:       000
                   01                                001
                   11                                011
                   10                                010
                                                     110
                                                     111
                                                     101
                                                     100
Today’s Skill: Dealing with ESD
What do you already know about ESD?
Typical Static Voltage Generation
          Source               10-20%        65-90%
                              humidity      humidity
 Walking on carpet           35,000 volts   1,500 volts
 Walking on vinyl flooring   12,000 volts     250 volts
 Worker at a bench            6,000 volts     100 volts
 Vinyl envelopes (Work        7,000 volts     600 volts
 Instructions
 Plastic bag picked up       20,000 volts   1,200 volts
 from the bench
 Work chair with foam pad    18,000 volts   1,500 volts

  NOTE -- It takes <100V to damage modern electronic
                      components
Typical Static Charge Sources
 Work surfaces   Waxed, painted or varnished surfaces
                 Glass
                 Untreated vinyl and plastics
 Floors          Sealed concrete
                 Waxed or finished wood
                 Floor tile and carpeting
 Clothes and     Non-ESD smocks
 personnel       Synthetic materials
                 Non-ESD Shoes
                 Hair
Typical Static Charge Sources
Chairs             Finished wood
                   Vinyl and Fiberglass
                   Nonconductive wheels
Packaging and      Plastic bags, wraps, envelopes
handling materials Styrofoam
                   Bubble wrap, foam
                   Non-ESD totes, trays, boxes, parts bins
Assembly tools     Pressure sprays
and materials      Copiers, printers
                   Compressed air
                   Synthetic brushes
                   Heat guns, blowers
  ESD damage prevention
 Combination of
     preventing static charges from developing
     eliminating static charge when present


***Need to ensure you do not have any
  static charge prior to handling electronic
  components
 Preventing and Eliminating Static
             Charge
 Keep electronic    components safe
     Conductive static-shielding boxes
     Antistatic bags and wraps
 Grounding Straps
 Heal Straps
 ESDShoes
 Smocks
ESD Safe Workstation
  General Rules for Handling
    Electronic Assemblies
 Keep work  stations clean and neat
 Minimize the handling of items
 Use clean gloves/hands
 Do not handle solderable surfaces with
  bare hands
 Do not use hand creams or lotions
  containing silicone
  General Rules for Handling
    Electronic Assemblies
 Never stack electronic assemblies
 Always assume the items are ESD
  Sensitive (ESDS) even if they are not
  marked
 Follow appropriate ESD practices and
  procedures
 Never transport ESDS devices unless
  proper packaging is applied
                    ESD Movie
 Let her   roll!
               Homework
 HW   2: Chapt 2 Probs: 1, 3, 5
                        Summary
   Topics:
       Digital & Analog Systems
       Number Systems
         • Binary (Base 2)
         • Hexadecimal (Base 16)
       Binary Codes
         • Binary Coded Decimal (BCD)
         • ASCII Code
         • Gray Code
   New Skill:
       Dealing with ESD
                  Next Time
 Boolean algebra
     Basic operators
     Truth tables
     Expressions
 Logic Gates

				
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