AVR Mega8 Architecture
AVR Programming Interface
Demo: ‘Hello World’ AVR Design.
Demo: Hardware Design
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
with a minimum of
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
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
RISC architecture with mostly fixed
store memory access and 32
stage instruction pipeline that speeds
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.
Available 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.
512 Byte EEPROM
6 or 8 Channel 10
Up to 16 MIPS
throughput at 16 Mhz.
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
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
MOSI: The data signal that sends the bits to be written to
MISO: The data signal that receives the bits read from the
These three signal pins are internally connected to the
programming machine only if you change the RESET pin
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
have to take care, that these two purposes do not
Usually you then decouple these by resistors or by use of a
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
The purpose of this
to design a simple AVR
Interface it to and LCD
Program it to display
Include the following files in your project
Add a new c source file to your AVR Studio
Type in the main function as shown below:
lcdPrintData(“Hello Word!”, 11);