Microcontrollers,
Microcomputers, and
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A microcontroller is a small, low cost computer on a single
integrated circuit.
ATmega328 Microcontroller
• Processor • Memory
• Programmable Input/Output(I/O)
Microcontroller, Microcomputer, or Microprocessor?
What is the difference?
Arduino Uno Microcontroller Board
SparkFun Electronics, . Arduino Uno - R3. 2013. Photograph. Wikipedia Commons Web. 7 Jan 2014.
Microcontrollers are used to perform one dedicated task. One specific program.
A microcomputer is a small, relatively inexpensive computer with a microprocessor as its
central processing unit. It includes:
• a microprocessor • memory
• input/output (I/O) facilities
Microcontroller, Microcomputer, or Microprocessor?
What is the difference?
Commodore 64 Microcomputer
Evan-Amos, . Commodore-64-Computer. 2011. Photograph. Wikipedia Commons Web. 7 Jan 2014.
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Why is it called a “micro” computer? Early computers such as
ENIAC filled entire rooms.
A “micro”computer by comparison with a keyboard, monitor, and
mouse are commonly referred to as a personal computer today.
The prefix “micro” is not commonly used in describing computers
anymore.
Microcontroller, Microcomputer, or Microprocessor?
What is the difference?
U.S. Army Photo, . ENIAC. 197. Photograph. Wikipedia Commons Web. 7 Jan 2014.
Microcontroller, Computer, or Processor?
What is the difference?
Application Processors
As the use of smart phones and mobile devices has
expanded, a new type of
processor has been defined.
Today, microprocessors in computers are often just referred to as processors. All computers today have a processor as the CPU.
Microprocessors designed for use in mobile applications are called application processors.
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Microcontroller, Microcomputer, or Microprocessor?
What is the difference?
A microprocessor is an IC which has only the Central Processing Unit inside them. They only have processing powers. Microprocessors don’t have RAM, ROM, and other peripheral on the chip.
A system designer has to add them externally to make them functional. Once again, the prefix “micro” is
increasingly left today in favor of just processor.
What is a Microcontroller?
Microcontrollers are used to control many everyday products like garage door openers, traffic lights, home thermostats, and robots. Embedded controllers are everywhere.
What are the Parts of a
Microcontroller?
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Microcontrollers contain:
• A Central Processing Unit (CPU)
• Some form of memory (MEMORY)
• Programmable Input / Output (I/O)
What are the Parts of the
Arduino Microcontroller Board?
The Arduino Microcontroller Board Specifications: • (14) Digital I/O Pins:
(6) are PWM Specific • (6) Analog I/O Pins
• Power: USB or external. If using power supply with 2.1mm center-positive plug, recommend range 7V-12V. • USB Connection: Type B • 5V or 3.3V option
Analog Digital / PWM
USB
Vext
Programming a Microcontroller
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Programming languages have
their own grammar called syntax.
Programs written with the Ardiuno
software are called Sketches.
A Sketch
(program written with Arduino) will contain:
• Variables • Functions
• Setup() • Loop() • Structures • Comments
Programming a Microcontroller
• The Arduino software consists of an Integrated development environment (IDE) and the core libraries. • The core libraries are written
in C and C++ and compiled using avr-gcc and AVR Libc. • The Arduino software
language you program in is very similar to C++ because it is derived from C/C++.
Example: Blink
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This sketch (program) will
continue to turn on LED on for 1 second and off for 1 second.
The sketch (program) includes :
setup() function - Initializes
variables, pin modes, start using libraries, etc.
loop() function - loops code consecutively.
Example: Blink
void - The void keyword is used
only in function declarations. It indicates that the function is
expected to return no information to the function from which it was called.
Example: Blink
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Syntax: { } Curly Braces
(also referred to as just "braces" or as "curly brackets")
Curly Braces are a major part of the C programming language.
Balanced Braces - An opening curly brace "{" must always be followed by a closing curly brace "}".
Example: Blink
Curly Braces –
Beginning programmers, and programmers coming to C from the BASIC language often find using braces confusing or
daunting.
The same curly braces in C replace:
the RETURN statement in a subroutine (function), the ENDIF statement in a conditional and
Example: Blink
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Syntax: The main uses of { } Curly Braces
Functions
void myfunction(datatype argument){ statements(s)
}
Loops
while (boolean expression) { statement(s) } do { statement(s)
} while (boolean expression);
for (initialisation; termination condition; incrementing expr)
{
statement(s) }
Conditional statements
if (boolean expression) {
statement(s) }
else if (boolean expression) { statement(s) } else { statement(s) }
Example: Blink
/* Blink
Turns on an LED on for one second, then off for one second, repeatedly. This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards. // give the variable “integer” the name “led”:
intled = 13;
// the setup routine runs once to declare function when you press reset:
void setup() {
// initialize the digital pin “pinMode” you defined as “led” as an output.
pinMode(led, OUTPUT); }
// the void loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
Example: Blink
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/* Blink
Turns on an LED on for one second, then off for one second, repeatedly. This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards. // give the variable “integer” the name “led”:
intled = 13;
A variable is a place for storing a piece of data. It has a type, a name, and a value.
For example, the Blink sketch declares a variable with:
Example: Blink
Variable Data Types Include: void
boolean char
unsigned char byte
int
unsigned int word
unsigned long short
float double
string - char array String - object
Array long
Example: Blink
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/* Blink
Turns on an LED on for one second, then off for one second, repeatedly. This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards. // give the variable “integer” the name “led”:
intled = 13;
// the setup routine runs once to declare function when you press reset:
void setup() {
// initialize the digital pin “pinMode” you defined as “led” as an output.
pinMode(led, OUTPUT); }
A function (also known as a sub-routine) is a named piece of code that can be used from elsewhere in the code.
The setup() function in this example sets the variable
Example: Blink
// the void loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
The loop() function loops consecutively, allowing your
program to change and respond.
Use it to actively control the Arduino board.
/* Blink
Turns on an LED on for one second, then off for one second, repeatedly. This example code is in the public domain.
*/
Your Turn
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Open Source Community
Arduino Software is free. You can install it at home if you
would like to continue work on your DE projects and/or create new projects of your own.
For the newest version of Aurdino IDE visit their website. In the next activities, you will program a microcontroller to
integrate new types of sensors and input devices.
Memsic 2125
Dual-axis Accelerometer 2-Axis Joystick
PIR Sensor
