Use the 6-pin ICSP header on Arduino Nano (best reliability): ICSP Header Location on Nano: ┌─────────────────────────────┐ │ ┌──┬──┐ │ │ │ │ │ ← = Pin 1 ...
Since you lacked the USB interface in your own Arduino board, it becomes necessary to use a homemade/ready-made USB to Serial Converter Module as an efficient and economical solution. Inexpensive and ...