The ATMega328P From (Almost) Nothing: 5. Flashing The Microcontroller
module ISP-1-20 | Programming adapter | Elnec
Atmel ISP Programmer
AS-ISP-CABLE Standard ISP cable for ChipProg-ISP programmer
Amazon.com: Geekstory for ATMEL 51 AVR USB ISP ASP Microcontroller Programmer Downloader with Cable + 10Pin to 6Pin Adapter Board for Ender 3 or Ender 3 Pro : Electronics