The CH55x-based picoISP is a simple and cheap USB-based in-system programmer (ISP) for AVR microcontrollers with voltage selection switch (5V and 3.3V) and compatible with the USBtinyISP, the USBasp, or the STK500 depending on the firmware. The picoISP supports a wide range of AVR microcontrollers, including the ATtiny and ATmega series, and can be used with a variety of software development tools such as the Arduino IDE, Atmel Studio, and AVRDUDE.