Introducing MicrocontrollersAbout AVRAVR Mega8 ArchitectureAVR Programming InterfaceDemo: ‘Hello World’ AVR Design.Demo: Hardware DesignDemo: Programming

A microprocessor is a central processing unit (CPU) on a single chip.

When a microprocessor and associated support circuitry, peripheral I/O components and memory (program as well as data) were put together to form a small computer specifically for data acquisition and control applications, it was called a microcomputer.

When the components that make a microcomputer were put together on a single chip of silicon, it was called the microcontroller.

A microcontroller interfaces to external devices with a minimum of external components

A recent white paper by Sun Microsystems claims that by the end of the decade, an average home will contain between 50 to 100 microcontrollers controlling digital phones, microwave ovens, VCRs, televisions sets and television remotes, dishwashers, home security systems, PDAs etc.

An average car has about 15 processors; the 1999 Mercedes S-class car has 63 microprocessors, while the 1999 BMW has 65 processors!

Except perhaps the human body, microprocessors and microcontrollers have gotten into everything around us.

RISC architecture with mostly fixed-length instruction, load-store memory access and 32 general-purpose registers.

A two-stage instruction pipeline that speeds up execution

Majority of instructions take one clock cycle

Up to 10-MHz clock operation

Wide variety of on-chip peripherals, including digital I/O, ADC, EEPROM, Timer, UART, RTC timer, PWM etc

Internal program and data memory. In-System programmableAvailable in 8-pin to 64-pin size to

suit wide variety of applications

Up to 12 times performance speedup over conventional CISC controllers.

Wide operating voltage from 2.7V to 6.0V

Simple architecture offers a small learning curve to the uninitiated.

8-Kbyte self-programming Flash Program Memory

1-Kbyte SRAM 512 Byte EEPROM 6 or 8 Channel 10-bit

A/D-converter. Up to 16 MIPS

throughput at 16 Mhz.

2.7 - 5.5 Volt operation.

The AVR chip has a built in interface, that enables you to write and read the content of the program flash and the built-in-EEPROM. This interface works serially and needs three signal lines: SCK: A clock signal that shifts the bits to be written

to the memory into an internal shift register, and that shifts out the bits to be read from another

internal shift register, MOSI: The data signal that sends the bits to be

written to the AVR, MISO: The data signal that receives the bits read

from the AVR.

These three signal pins are internally connected to the programming machine only if you change the RESET pin to zero.

Otherwise, during normal operation of the AVR, these pins are programmable I/O lines like all the others.

If you like to use these pins for other purposes during normal operation, and for in-system-programming, you'll have to take care, that these two purposes do not

conflict. Usually you then decouple these by resistors or by

use of a multiplexer. What is necessary in your case, depends from

your use of the pins in the normal operation mode.

VTG: Target Voltage

LED: indicates that the programmer is doing its job

The purpose of this demo is: to design a simple

AVR system Interface it to and

LCD display Program it to

display ‘Hello World’

Programmer

AVR MCUAVR MCU

LCD DisplayLCD Display

LCD Interface AVR Port

RS PORTC.2

RW PORTC.3

E PORTC.4

DATA PORTD

AVR StudioGCCAVRLibsPonyProg

Include the following files in your project lcd.c global.h timer.h lcd.h

Add a new c source file to your AVR Studio project.

Type in the main function as shown below:

Main(){

lcdInitHW(); lcdInit(); lcdGotoXY(0,4); lcdPrintData(“Hello Word!”, 11);

}