The Pololu USB AVR Programmer V2.1 is a low-cost in-system programmer (ISP) for Atmel AVR microcontrollers. It can be used to program any AVR microcontroller with a UPDI, JTAG, PDI, TPI, or SPI interface, including most 8-pin and 32-pin devices in the popular ATtiny and ATmega families. The programmer connects to a host computer's USB port and appears as a USB serial device. It is also equipped with a 6-pin ISP interface for in-system programming. The programmer is fully supported by both AVRDUDE and Atmel Studio, making it easy to use right out of the box.