Flashing Arduino bootloader - danielmcmillan/irrigation-system GitHub Wiki
After board manufacture, the ATmega microcontroller must be flashed using SPI.
This can be done using another board already having the Arduino firmware as a programmer.
- Connect the ICSP header of the two boards together, except for pin 5 (reset) which should go to another digital output pin of the programmer. The default is Arduino Digital 10, which is pin 7 (ASS) on the controller unit board IO header.
- Connect with UART to the board being used as the programmer, without connecting 5v.
- In the Arduino IDE, change Board to "Arduino Pro or Pro Mini" and processor to "ATmega328P 3.3V, 8 MHz"
- Upload the "ArduinoISP" example sketch to the board
- Change Programmer to "ArduinoISP" and run Burn Bootloader
Example using controller unit board to flash bootloader to a remote unit board: