AVR ISP Programmer

Amtel AVR Microcontrollers come in a number of variants. The one most Arduino users know is the 28 pin ATMega328 variant. However AVR chips come in 8-Pin, 14-Pin, 20-Pin and 40-Pin packages as well. The less pins on a chip mean less IO ports. The Digispark board which is an Arduino variant uses a ATTiny85 Microcontroller and has only 5 IO pins.

Arduino boards (eg Uno, Mega, Digispark) load software from the Arduino IDE via the USB port. This is only possible because the AVR Microcontroller on the board has already been programmed with a special piece of software called a bootloader. However when you purchase a new AVR Microcontroller, it will be blank and you cannot use the Arduino IDE to program sketches for it.

To program a blank AVR microcontroller, you need a special board such as the USBtinyISP programmer. The USBtinyISP allows you to download the software from your PC via a USB cable and program the chip. On the PC side, you run a program called Avrdude.exe. AVR Microcontr