AVR - microcontrollers is a powerful tool for creating modern high-performance and cost-effective multi-purpose devices.

The program for the microcontroller is written in any suitable programming language is compiled into a binary file (or file format intel HEX) and poured into the microcontroller through the programming .

programmer - is a device that connects a microcontroller and a computer and allows the computer to write the firmware file to the memory controller. Also need to flash a program that will drive a special protocol data to the microcontroller.

Methods microcontroller firmware using AVR-programmer :

1. In-circuit programming (ISP)

   This method sew modern controllers is the most popular to date. Internally it is called because the microcontroller when the firmware is in the scheme of the target device. For the needs of programming in this case stands out several conclusions controller (usually 3..5, depending on the controller).

   These findings are sewn cord connects the programmer and fill a firmware. After that, the cord is disconnected and the controller starts.

   At the AVR firmware is filled via SPI and for programming need four lines and power:  

   • MISO - data coming from the controller (Master-Input / Slave-Output)
   • MOSI - data going into the controller (Master-Output / Slave-Input)
   • SCK - SPI interface clock
   • RESET - RESET signal to the programmer enters the controller in programming mode
   • GND - earth

   For the implementation of the "serial" in-circuit programming is necessary:

   • connect programmer leg reset (RESET) and SPI interface controller (feet MOSI, MISO, SCK);
   • powered microcontroller nominal voltage of + 5V (GND, VCC).

   Programmers for in-firmware AVR controllers are distinguished by such features:

   • to speed;
   • the type of connection to the computer (COM / LPT / USB);
   • there with his master controller or not.

   Programmers without a master controller is very simple to manufacture and commissioning. They work exclusively through COM or LPT ports.

   Programmers are working with the master controller via COM, but also can work without problems via USB. But when dealing with these programmers is one problem: in order to make such a programmer, need another programmer to sew him master controller. The problem of "chicken and egg".

   The most popular programmers of this type:

   • USBASP
   • AVRDOPER
   • AVR910
    
2. Parallel high-voltage programming

   Normally used in the manufacture of chips with mass firmware in the programmer before they are sealed into the device.  

   Features of parallel programming

   • Many times faster sequential (ISP);
   • requires submission to the RESET voltage of 12 volts;
   • no longer requires 3 data lines and eight + control line;
   • microcontroller programmer inserted into the panel, and after the firmware is rearranged in the target device.

For radio amateur practice this method of programming is not needed, because ISP programmer solves 99% urgent tasks.