Algoritmos . Conceptos Básicos
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Transcript of Algoritmos . Conceptos Básicos
WEEK 1WHY COMPUTERS?
Algorithms
0. What is a Computer?Is a programmable machine
designed to sequentially and automatically carry out a secuence of aritmetic or logical aperations. The particular secuence of operations can be changed readily, allowing the computer to solve than one kind problem.
In the Beginning
ENIAC Electronic Numerical Integrator And Computer.
The first electronic digital computer developed for the U.S.
Started 1943 Programed by plugging in
cords and setting thousands of swiches.
18.000 vacuum tubes Weight 30 tons 1800 square feet 5000 additions per second It cost a fortune in
electricity to run. It was dismantled in 1955
Most people’s computer...Most people would be lost if all the computers in the world
went down at the same time.
CRT Display
Keyboard
Mouse
“The Box”CD-ROM Drive
FloppyDiskDrive
Inside “The Box”
Motherboard
CPU(Central Processing Unit)
SIMM(Single Inline Memory Module)
HDD(Hard Disk Drive)
Power Supply
Schematic Diagram of a Personal Computer...
Ports
CPU
RAM
Diskcontroller
Graphicscard
Soundcard
Networkcard
Printer
Mouse
Keyboard
Modem Monitor
Speakers
bus
Computer
Other Examples
Computing is Much, Much More...
Mobile Computing
Output Devices
Input Devices
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
OCR
El OCR (Optical character recognition) es un software de reconocimiento de texto que saca de una imagen el texto que contiene y lo transforma en cadenas de caracteres para guardarlos en un formato que se pueda utilizar en programas de edición de texto.
Si necesitamos extraer ese texto para poder editarlo, necesitamos un programa de OCR que reconozca dicho texto y lo transforme en una cadena de caracteres (ya sea ASCII o Unicode) y posteriormente copiar esta cadena a un programa de edición para ya poder trabajar con ella, con el consiguiente ahorro de tiempo al no tener que teclear este texto.
OCR
Hello, world
Page of text
Optical scan 10110110…
Computer file
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
Bar Codes
An automatic identification (Auto ID) technology that streamlines identification and data collection
See http://www.digital.net/barcoder/barcode.html
Código de barras
El código de barras consiste en un sistema de codificación creado a través de series de líneas y espacios paralelos de distinto grosor. Generalmente se utiliza como sistema de control ya que facilita la actividad comercial del fabricante y del distribuidor, por lo que no ofrece información al consumidor, si no datos de operaciones aplicados a identificar productos, llevar control de inventarios, carga y descarga de mercancías, disminuir tiempos de atención en ventas.
Una de las principales ventajas es que los datos almacenados en un código de barras puede ser leído de manera precisa y rápida.
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
Voice/audio Input
Input device: microphoneAudio input is “digitized” and storedProcessed in two ways
As is (no recognition) Recognized and converted to alphanumeric data
(ASCII)
Digitize
10110010…
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
Punched Cards
Invented by Herman Hollerith (founder of IBM)
Each card holds 80 characters
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
Images
Typically images are pictures that are optically scanned and saved as a “bit map” or in some other format
Many formats gif, jpeg, …
Typical “Save As” Dialog
Objects
Images made of geometrically definable shapes
Offer efficiency, flexibility, small size, etc.
Other Input
OCR – optical character recognitionBar code readersVoice/audio inputPunched cardsImages / objectsPointing devices
Pointing Devices
Originally used for specifying coordinates (x, y) for graphical input
Today used as general purpose device for “graphical user interfaces” (GUIs)
“Other” Computing
Roles
Busines: Computer can tabulate bills, calculate profit and loss, and predict the future of bussines. Things can be sold and bought on line, and computer are a major part of the stock marked.
Comunication: E-mail allow instant comunication all over the world. Computers save time and give you information at your fingertips. The Internet provides a fast and easy way to research any topic.
Daily life: we operate washing machines, microwave oven and many others products using software.
We can store all information about our work, appointments schedules and list of contacts.
we need to have the knowledge about all fields of the computers
Media
There is sofware for every kind of editing audio visual composition. Special efects rely heavily on computers.
Popular special effects seen in movies include fire, explosions, rain, snow and smoke. A number of movies also showcase effects that change the look of characters like those that make a person look older, younger or monstrous or transform into another person, creature or object.
Other roles
Medical science: Computers can help with
diagnosis, and there is special software wich assists doctors during surgery.
Travel and ticketing: Computers do all the
work of plane and train reservation. It shows the data for vacant and reserved seats and also saves the record for reservation
Sports: Computers can help
referees and umpire make decisions. Also, simulation software can help and atletic improve his or her skills.
Weather: Super computers take
data from observations and give meteorologist “models” to help them predict weather.
1. Number Systems
Common Number Systems
System Base SymbolsUsed by humans?
Used in computers?
Decimal 10 0, 1, … 9 Yes No
Binary 2 0, 1 No Yes
Octal 8 0, 1, … 7 No No
Hexa-decimal
16 0, 1, … 9,A, B, … F
No No
Quantities/Counting (1 of 3)
Decimal Binary OctalHexa-
decimal
0 0 0 0
1 1 1 1
2 10 2 2
3 11 3 3
4 100 4 4
5 101 5 5
6 110 6 6
7 111 7 7
Quantities/Counting (2 of 3)
Decimal Binary OctalHexa-
decimal
8 1000 10 8
9 1001 11 9
10 1010 12 A
11 1011 13 B
12 1100 14 C
13 1101 15 D
14 1110 16 E
15 1111 17 F
Quantities/Counting (3 of 3)
Decimal Binary OctalHexa-
decimal
16 10000 20 10
17 10001 21 11
18 10010 22 12
19 10011 23 13
20 10100 24 14
21 10101 25 15
22 10110 26 16
23 10111 27 17 Etc.
Conversion Among Bases
The possibilities:
Hexadecimal
Decimal Octal
Binary
Quick Example
2510 = 110012 = 318 = 1916
Base
Decimal to Decimal (just for fun)
Hexadecimal
Decimal Octal
Binary
Next slide…
12510 => 5 x 100 = 52 x 101 = 201 x 102 = 100
125
Base
Weight
Binary to Decimal
Hexadecimal
Decimal Octal
Binary
Binary to Decimal
Technique Multiply each bit by 2n, where n is the “weight” of the
bit The weight is the position of the bit, starting from 0
on the right Add the results
Example
1010112 => 1 x 20 = 11 x 21 =
20 x 22 =
01 x 23 =
80 x 24 =
01 x 25 =
32
4310
Bit “0”
Octal to Decimal
Hexadecimal
Decimal Octal
Binary
Octal to Decimal
Technique Multiply each bit by 8n, where n is the “weight” of the
bit The weight is the position of the bit, starting from 0
on the right Add the results
Example
7248 => 4 x 80 = 42 x 81 = 167 x 82 = 448
46810
Hexadecimal to Decimal
Hexadecimal
Decimal Octal
Binary
Hexadecimal to Decimal
Technique Multiply each bit by 16n, where n is the “weight” of
the bit The weight is the position of the bit, starting from 0
on the right Add the results
Example
ABC16 => C x 160 = 12 x 1 = 12 B x 161 = 11 x 16 = 176 A x 162 = 10 x 256 = 2560
274810
Decimal to Binary
Hexadecimal
Decimal Octal
Binary
Decimal to Binary
Technique Divide by two, keep track of the remainder First remainder is bit 0 (LSB, least-significant bit) Second remainder is bit 1 Etc.
Example
12510 = ?22 125 62 12 31 02 15 12 7 12 3 12 1 12 0 1
12510 = 11111012
Octal to Binary
Hexadecimal
Decimal Octal
Binary
Octal to Binary
Technique Convert each octal digit to a 3-bit equivalent binary
representation
Example
7058 = ?2
7 0 5
111 000 101
7058 = 1110001012
Hexadecimal to Binary
Hexadecimal
Decimal Octal
Binary
Hexadecimal to Binary
Technique Convert each hexadecimal digit to a 4-bit equivalent
binary representation
Example
10AF16 = ?2
1 0 A F
0001 0000 1010 1111
10AF16 = 00010000101011112
Decimal to Octal
Hexadecimal
Decimal Octal
Binary
Decimal to Octal
Technique Divide by 8 Keep track of the remainder
Example
123410 = ?8
8 1234 154 28 19 28 2 38 0 2
123410 = 23228
Decimal to Hexadecimal
Hexadecimal
Decimal Octal
Binary
Decimal to Hexadecimal
Technique Divide by 16 Keep track of the remainder
Example
123410 = ?16
123410 = 4D216
16 1234 77 216 4 13 = D16 0 4
Binary to Octal
Hexadecimal
Decimal Octal
Binary
Binary to Octal
Technique Group bits in threes, starting on right Convert to octal digits
Example
10110101112 = ?8
1 011 010 111
1 3 2 7
10110101112 = 13278
Binary to Hexadecimal
Hexadecimal
Decimal Octal
Binary
Binary to Hexadecimal
Technique Group bits in fours, starting on right Convert to hexadecimal digits
Example
10101110112 = ?16
10 1011 1011
2 B B
10101110112 = 2BB16
Octal to Hexadecimal
Hexadecimal
Decimal Octal
Binary
Octal to Hexadecimal
Technique Use binary as an intermediary
Example
10768 = ?16
1 0 7 6
001 000 111 110
2 3 E
10768 = 23E16
Hexadecimal to Octal
Hexadecimal
Decimal Octal
Binary
Hexadecimal to Octal
Technique Use binary as an intermediary
Example
1F0C16 = ?8
1 F 0 C
0001 1111 0000 1100
1 7 4 1 4
1F0C16 = 174148
Exercise – Convert ...
Don’t use a calculator!
Decimal Binary OctalHexa-
decimal
33
1110101
703
1AF
Skip answer Answer
Exercise – Convert …
Decimal Binary OctalHexa-
decimal
33 100001 41 21
117 1110101 165 75
451 111000011 703 1C3
431 110101111 657 1AF
Answer
Common Powers (1 of 2)
Base 10Power Preface Symbol
10-12 pico p
10-9 nano n
10-6 micro
10-3 milli m
103 kilo k
106 mega M
109 giga G
1012 tera T
Value
.000000000001
.000000001
.000001
.001
1000
1000000
1000000000
1000000000000
Common Powers (2 of 2)
Base 2Power Preface Symbol
210 kilo k
220 mega M
230 Giga G
Value
1.024
1.048.576
1.073.741.824
• What is the value of “k”, “M”, and “G”?• In computing, particularly w.r.t. memory, the base-2 interpretation generally applies
Example
/ 230 =
In the lab…1. Double click on My Computer2. Right click on C:3. Click on Properties
Exercise – Free Space
Determine the “free space” on all drives on your computer
DriveFree space
Bytes GB
A:
C:
D:
E:
etc.
Review – multiplying powers
For common bases, add powers
26 210 = 216 = 65,536
or…
26 210 = 64 210 = 64k
ab ac = ab+c
Binary Addition (1 of 2)
Two 1-bit values
A B A + B0 0 00 1 11 0 11 1 10
“two”
Binary Addition (2 of 2)
Two n-bit values Add individual bits Propagate carries E.g.,
10101 21+ 11001 + 25 101110 46
11
Multiplication (1 of 3)
Decimal (just for fun)
35x 105 175 000 35 3675
Multiplication (2 of 3)
Binary, two 1-bit values
A B A B0 0 00 1 01 0 01 1 1
Multiplication (3 of 3)
Binary, two n-bit values As with decimal values E.g.,
1110 x 1011 1110 1110 0000 111010011010
Fractions
Decimal to decimal (just for fun)
3.14 => 4 x 10-2 = 0.041 x 10-1 = 0.1
3 x 100 = 3 3.14
Fractions
Binary to decimal
10.1011 => 1 x 2-4 = 0.06251 x 2-3 = 0.1250 x 2-2 = 0.251 x 2-1 = 0.50 x 20 = 0.01 x 21 = 2.0 2.6875
Fractions
Decimal to binary3.14579
.14579x 20.29158x 20.58316x 21.16632x 20.33264x 20.66528x 21.33056
etc.11.001001...
Exercise – Convert ...
Don’t use a calculator!
Decimal Binary OctalHexa-
decimal
29.8
101.1101
3.07
C.82
Skip answer Answer
Exercise – Convert …
Decimal Binary OctalHexa-
decimal
29.8 11101.110011… 35.63… 1D.CC…
5.8125 101.1101 5.64 5.D
3.109375 11.000111 3.07 3.1C
12.5078125 1100.10000010 14.404 C.82
Answer
2. Data Formats
Introduction
ExamplesReal World
Data
Computer
DataInput device
Dear Mom: Keyboard 10110010…
Digitalcamera
10110010…
Format must be appropriate
The internal representation must be appropriate for the type of processing to take place (e.g., text, images, sound)
Standards Organizations
ISO – International Standards OrganizationCSA – Canadian Standards AssociationANSI – American National Standards
InstituteIEEE – Institute for Electrical and Electronics
EngineersEtc.
Examples of Standards
Type of Data Standards
Alphanumeric ASCII, EBCDIC, Unicode
Image JPEG, GIF, PCX, TIFF
Motion picture MPEG-2, Quick Time
Sound Sound Blaster, WAV, AU
Outline graphics/fonts PostScript, TrueType, PDF
Why Standards?
Standard are “arbitrary”They exist because they are
Convenient Efficient Flexible Appropriate Etc.
Alphanumeric Data
Problem: Distinguishing between the number 123 (one hundred and twenty-three) and the characters “123” (one, two, three)
Four standards for representing letters (alpha) and numbers BCD – Binary-coded decimal ASCII – American standard code for information
interchange EBCDIC – Extended binary-coded decimal
interchange code Unicode
Next 2 slides
Standard Alphanumeric Formats
BCDASCIIEBCDICUnicode
Binary-Coded Decimal (BCD)
Four bits per digit Digit Bit pattern
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001
Note: the following bit patterns are not used:
101010111100110111101111
Example
709310 = ? (in BCD)
7 0 9 3
0111 0000 1001 0011
Next 22 slides
Standard Alphanumeric Formats
BCDASCIIEBCDICUnicode
The Problem
Representing text strings, such as “Hello, world”, in a computer
Codes and Characters
Each character is coded as a byteMost common coding system is ASCII
(Pronounced ass-key)ASCII = American National Standard Code
for Information InterchangeDefined in ANSI document X3.4-1977
ASCII Features
7-bit code8th bit is unused (or used for a parity bit)27 = 128 codesTwo general types of codes:
95 are “Graphic” codes (displayable on a console) 33 are “Control” codes (control features of the console
or communications channel)
ASCII Chart
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Most significant bit
Least significant bit
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
e.g., ‘a’ = 1100001
95 Graphic codes
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
33 Control codes
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Alphabetic codes
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Numeric codes
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Punctuation, etc.
“Hello, world” Example
============
Binary010010000110010101101100011011000110111100101100001000000111011101100111011100100110110001100100
Hexadecimal48656C6C6F2C207767726C64
Decimal72
1011081081114432
119103114108100
Hello, world
============
============
Common Control Codes
CR 0D carriage returnLF 0A line feedHT 09 horizontal tabDEL 7F deleteNULL 00 null
Hexadecimal code
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Terminology
Learn the names of the special symbols [ ] brackets { } braces ( ) parentheses @ commercial ‘at’ sign & ampersand ~ tilde
000 001 010 011 100 101 110 1110000 NULL DLE 0 @ P ` p0001 SOH DC1 ! 1 A Q a q0010 STX DC2 " 2 B R b r0011 ETX DC3 # 3 C S c s0100 EDT DC4 $ 4 D T d t0101 ENQ NAK % 5 E U e u0110 ACK SYN & 6 F V f v0111 BEL ETB ' 7 G W g w1000 BS CAN ( 8 H X h x1001 HT EM ) 9 I Y i y1010 LF SUB * : J Z j z1011 VT ESC + ; K [ k {1100 FF FS , < L \ l |1101 CR GS - = M ] m }1110 SO RS . > N ^ n ~1111 SI US / ? O _ o DEL
Escape Sequences
Extend the capability of the ASCII code setFor controlling terminals and formatting
outputDefined by ANSI in documents X3.41-1974
and X3.64-1977The escape code is ESC = 1B16
An escape sequence begins with two codes:
ESC [ 1B1
6
5B1
6
Next 1 slides
Standard Alphanumeric Formats
BCDASCIIEBCDICUnicode
EBCDIC
Extended BCD Interchange Code (pronounced ebb’-se-dick)
8-bit codeDeveloped by IBMRarely used todayIBM mainframes only
Next 2 slides
Standard Alphanumeric Formats
BCDASCIIEBCDICUnicode
Unicode
16-bit standardDeveloped by a consortiaIntended to supercede older 7- and 8-bit
codes
Unicode provides a unique number for every character,
no matter what the platform,no matter what the program,no matter what the language.
Unicode Version 2.1
1998Improves on version 2.0 Includes the Euro sign (20AC16 = ) From the standard:
…contains 38,887 distinct coded characters derived from the supported scripts. These characters cover the principal written languages of the Americas, Europe, the Middle East, Africa, India, Asia, and Pacifica.
http://www.unicode.org
Keyboard Input
Key (“scan”) codes are converted to ASCIIASCII code sent to host computerReceived by the host as a “stream” of dataStored in bufferProcessedEtc.
Shift Key
inhibits bit 5 in the ASCII code
Key(s)ASCII code
6 5 4 3 2 1 0 Character
1 1 0 0 0 0 1
1 0 0 0 0 0 1
a
A
a
aShift
Control Key
inhibits bits 5 & 6 in the ASCII code
Key(s)ASCII code
6 5 4 3 2 1 0 Character
1 1 0 0 0 1 1
0 0 0 0 0 1 1
c
ETX
c
cCtrl
Controlcode
Thank you
Tomado de Universidad de Nueva York
http://www.cse.yorku.ca/~mack/1011/