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 microcontrollerinterfaces toexternal deviceswith a minimum ofexternalcomponents
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 programmable 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.
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, youll 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 Programmer Interface it to and LCD display AVR MCU AVR MCU Program it to display ‘Hello World’ LCD Display LCD Display