Simple and easy way to use Arduino Uno as ATtiny programmer.
0. Turn the Arduino into a AVRISP
(AVR is a family of microcontrollers. ISP means In System Programmer)
Connect Arduino and open Arduino IDE -> File -> Examples -> 11.ArduinoISP ->ArduinoISP and upload to Arduino.
1. Install hardware package for ATtiny85
1.1 Open Arduino IDE -> File -> Preferences go to Additional Boards Manager URLs and copy this: http://drazzy.com/package_drazzy.com_index.json
1.2 Open Arduino IDE -> Tools -> Board -> Boards manager. Find “ATtinyCore by Spence Konde” and click Install.
More about ATtinyCore: https://github.com/SpenceKonde/ATTinyCore
2. Connect the hardware
3. Arduino IDE settings
Go to Arduino IDE -> Tools and select:
- Board: “ATtiny 25/45/85”
- Chip: “ATtiny85”
- Clock: 8 MHz internal
- B.O.D Level: “B.O.D. Disabled”
- Save EEPROM: “EEPROM retained”
- Timer 1 clock: “CPU”
- LTO: “Disabled”
- Port: (Your Arduino port)
- Programmer: “Arduino as ISP”
4. Burn Bootloader
(You only need to do this once per chip)
Go to Arduino IDE -> Tools -> Burn Bootloader
5. Upload sketch
Go to: Arduino IDE -> Sketch -> Upload Using Programmer
Tauno Erik 
Arduino:1.8.13 (Windows Store 1.8.42.0) (Windows 10), Kort”ATtiny25/45/85, ATtiny85, External 8 MHz”
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
Feil oppstod under skriving av oppstartslaster.
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x03
Check connections, wirings. Upload using Arduino as a programmer.
“External 8 MHz is a mistake”, the good way is” Internal 8MHZ”