Intro to micro controller (Atmega16)

 What’s Embedded System ?
 Examples on Embedded System
 What’s Microcontroller?
 MicroProcessor Vs. MicroController
 Components of Microcontroller
 Vendors of Microcontrollers
 AVR History
 AVR Categories
 Why AVR ?
 Atmega 16 and it’s Flavour

 Embedded System : it’s a special system with dedicated
functionality.
 Word “Embedded” come from the fact these system are hidden or a
part of large system, also multiple embedded system can co-exist in
one embedded system.
 We can use microcontroller Or microprocessor to implement this
system.

 It’s a full computer on one chip but it’s resources are
far from limited than of a desktop personal
computer.
 This single chip contain CPU, Non-volatile memory
(ROM) , volatile memory (RAM), Timer & I/O port ,
so we can call it computer on chip.
 Briefly, Micro-controller is Many IC into one IC.
 Note:
There is NO micro-controller work alone in circuit
it must interface with other peripherals like
sensors, motors, LCD…….. etc.

 Microprocessor
Central Processing Unit (CPU), is the brain of
all computers and many household and
electronic devices.
 Just a CPU has to add externally memory, clock,
input/output interfaces, timer and all other needed
peripheral. This is the reason a microprocessor has
so many pins.

Micro-controller
 Microcontroller is a computer
dedicated to one or just a few tasks &
no need to other peripherals.
 Contain Memory ,timer and many,
but can’t add peripherals to chip
 Can do one task or few task
Microprocessor
 Microprocessor is a general purpose
computer which need other
peripherals to operate.
 No Memory , Timer & clock, but you
can add this peripherals to it.
 Can do many task.

 Microprocessor :
It refers to central processing unit (CPU) of the
microcontroller.
It contain ALU (arithmetic logic unit),Control unit
,instruction Decoder ,some special register (Stack
pointer , status register , program counter , etc.)
 Volatile data memory (RAM)
 From it’s name, data is volatile.
 used by the microcontroller for temporary data
storage and erased if the device power went off
 Microprocessor take long time to access it

 Non-Volatile data memory (ROM):
Opposite to RAM
Used to save the code and temporary data and
doesn’t be erased if power went off.
It takes much longer than RAM to be accessed by
CPU.
 Timer Module:
Most microcontrollers have at least one
timer/counter peripheral.
Timer/Counter modules are used to perform
timing or counting operations in the controller.

 Interrupt Module:
Interrupts enable the microcontroller to
monitor certain events in the background
while executing and application program
and react to the event if necessary pausing
the original program.
This is all coordinated by the interrupt
module.
 Digital I/O Module:
This mode allow to microcontroller to deal
with external world.
It can be used to drive actuators or sense
signal from sensor.

 Serial Module:
This module deal with serial
communication with external world.
Examples : ISP,USART,I2C(two wire
interface).
 Analog I/O Module:
This module responsible for reading
or writing analog signals.
This module contain analog
comparator and analog to digital
converter.

Vendor Families Derivatives
AVR Atmega16
8051 AT83EB5114
PIC PIC16F877A
HC12 MC9S12XEP100
V850 V850ES
TM4C TM4C123GH6PM

 AVR was developed in 1996 by Atmel
cooperation.
 The two person who developed AVR was Alf-
egil & vegard wollan.
 The name AVR came after the name of its
developer Alf-egil bogen Vegard Wollan Risc
microcontroller.
 Also known by Advanced Virtual Risc.
 First microcontroller to hit the market was
AT90S1200 in the year 1997

 Tiny AVR
Less memory.
small size.
suitable only for simpler applications.
 Mega AVR
These are the most popular ones.
having good amount of memory (up to 256 KB) higher number of inbuilt
peripherals.
suitable for moderate to complex applications.
 Xmega AVR
Used commercially for complex applications, which require large
program memory and high speed.

 AVR micro-controllers are fast executes
most of the instructions in single execution
cycle.
 AVRs are about 4 times faster than PICs.
 They consume less power and can be
operated in different power saving modes.
 Free IDE.
 Available in Egyptian market.

8051 AVR PIC
Speed Slow Fast Moderate
Memory Small Large Large
Architecture CISC RISC RISC
ADC Not present Inbuilt Inbuilt
Timers Inbuilt Inbuilt Inbuilt
PWMs Not present Inbuilt Inbuilt

 ATmega16: Operating frequency range is 0 – 16 MHz .
 ATmega16L: Operating frequency range is 0 – 8 MHz .
If we are using a crystal of 8 MHz = 8 x 106 Hertz = 8
Million cycles, then AVR can execute 8 million add
instructions per second.

What’s Register ?
It’s an electronic circuit that can memorize the state of one
byte or more.

Register can be used to control µc also it make µc faster
and can do many task in few milliseconds.
µc consists of many register like :
DDRx,PORTx,PINx.
SREG (Status I/O register).
MCUCR (MCU Control Register).
TCCR0 (Timer/Counter Control Register).

 I/O Ports
 ATmega16 has four (PORTA, PORTB, PORTC and PORTD) 8-bit input-
output ports.
 Timers/Counters
 ATmega16 consists of two 8-bit and one 16-bit timer/counter.
 Watchdog Timer
 Present with internal oscillator. Watchdog timer continuously monitors
and resets the controller if the code gets stuck at any execution action
for more than a defined time interval.
 ADC Interface
 ATmega16 is equipped with an 8 channel ADC with a resolution of 10-
bits.

 Analog Comparator
 The Analog Comparator compares the input values of two analog
signals.
 Interrupt Unit
 Consists of 21 interrupt sources out of which four are external. The
remaining are internal interrupts which support the peripherals like
USART, ADC, Timers etc.
 USART
 Universal Synchronous and Asynchronous Receiver and Transmitter
interface is available for interfacing with external device capable of
communicating serially (data transmission bit by bit).

 TWI(Two Wire Interface )
 Also called Inter-integrated Circuits can be used to set up a network of
devices, many devices can be connected over TWI interface forming a
network, the devices can simultaneously transmit and receive and have
their own unique address.
 SPI (Serial Peripheral Interface)
 Used for serial communication between two devices on a common clock
source.
 ISP(In System Programmable )
 Flash Memory which can be programmed without removing the IC from
the circuit.

http://maxembedded.com/
http://extremeelectronics.co.in/
http://www.embedds.com/avr-tutorials/
http://avr-tutorials.com/
http://www.instructables.com/

Intro to micro controller (Atmega16)

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