CERN Open Hardware License
This project is a simple programmer for burning a bootloader on the ATMEGA328P using arduino as ISP before it is soldered unto a board. The instructions here https://www.instructables.com/id/Burn-a-New-Bootloader-Arduino-Pro-Mini/ for using an Arduino as ISP can be followed. Please note that this design saves you from having to make all the connections as shown in the instructable. Simply place a new ATMEGA328P in the adapter and continue from the "Third Step " in the instructable.
The onboard controller was designed to be a 328P but can be substituted with an ATMEGA88 or ATMEGA168.
I used a TQFP32 QFP32 TO DIP32 IC Programmer Adapter which plugs into the 32pin DIL as a holder for the ATMEGA328P to be programmed. It can be purchased online from aliexpress using this link https://www.aliexpress.com/item/TQFP32-QFP32-TO-DIP32-IC-Programmer-Adapter-Chip-Test-Socket-SA663-Burning-Seat-Integrated-Circuits/32885926613.html?spm=a2g0s.90423184.108.40.206f4c4d9yeSJK.
This device is useful if you have to burn bootloader to a number of controllers before assembly.