ATtiny85 is a small and powerful microcontroller for small applications. Programming the ATtiny85 with Arduino UNO is somewhat difficult than directly with USB. For programming the ATtiny85 directly from PC or laptops using USB requires Micronucleus bootloader to be burned or flashed on the ATtiny85 chip. Once it is flashed with the Micronucleus bootloader, it is very easy to program it directly by connecting to PC or Laptop via USB cable.
Connect the Arduino to the ATtiny as follows:
Arduino +5V —> ATtiny VCC
Arduino Ground —> ATtiny GND
Arduino Pin 10 —> ATtiny P5
Arduino Pin 11 —> ATtiny P0
Arduino Pin 12 —> ATtiny P1
Arduino Pin 13 —> ATtiny P2
Connect the 10uF Capacitor as follows:
Arduino pin Reset —> Capacitor positive
Arduino pin ground —> Capacitor negative
Attiny Library Link:
Digispark Library Link
Following Attachment Contains the t85_default.hex and the command which is to be executed at the command prompt.
Download this —> Attachment