NOTE! When connecting and referencing pins, use the Arduino pin number! For example, use pin 2 a.k.a D2 in code instead of physical pin 4.
From the root of this repository, open Main.ino
Click the Arduino/Verify button at the top right. (Opt+Cmd+R)
The output of the compilation goes into the build directory(ignored in Git). Inside this directory you'll find two .hex files, with and without the bootloader. We can use usually the one without the bootloader because it's already in flash.
Send the compiled .hex to the Raspberry pi for flashing:
$ scp Main.ino.hex [email protected]:/home/pi
On the Raspberry Pi:
Flash the .hex file:
sudo avrdude -P gpio -c gpio -p atmega328p -U flash:w:Main.ino.hex
That's it for updating the Arduino firmware. From here the Raspberry Pi code can be executed to communicate with the Arduino over I2C.