From the root directory run make PROJECT:KEYMAP:avrdude for automatic serial port resolution and flashing. Example: make not_so_minidox/rev1:default:avrdude

Choosing which board to plug the USB cable into (choosing Master)

Because the two boards are identical, the firmware has logic to differentiate the left and right board.

It uses two strategies to figure things out: look at the EEPROM (memory on the chip) or looks if the current board has the usb cable.

The EEPROM approach requires additional setup (flashing the eeeprom) but allows you to swap the usb cable to either side.

The USB cable approach is easier to setup and if you just want the usb cable on the left board, you do not need to do anything extra.

Setting the left hand as master

If you always plug the usb cable into the left board, nothing extra is needed as this is the default. Comment out EE_HANDS and comment out I2C_MASTER_RIGHT or MASTER_RIGHT if for some reason it was set.

Setting the right hand as master

If you always plug the usb cable into the right board, add an extra flag to your config.h

 #define MASTER_RIGHT

Setting EE_hands to use either hands as master

If you define EE_HANDS in your config.h, you will need to set the EEPROM for the left and right halves.

The EEPROM is used to store whether the half is left handed or right handed. This makes it so that the same firmware file will run on both hands instead of having to flash left and right handed versions of the firmware to each half. To flash the EEPROM file for the left half run:

avrdude -p atmega32u4 -P $(COM_PORT) -c avr109 -U eeprom:w:"./quantum/split_common/eeprom-lefthand.eep"
// or the equivalent in dfu-programmer

and similarly for right half

avrdude -p atmega32u4 -P $(COM_PORT) -c avr109 -U eeprom:w:"./quantum/split_common/eeprom-righthand.eep"
// or the equivalent in dfu-programmer

NOTE: replace $(COM_PORT) with the port of your device (e.g. /dev/ttyACM0)

After you have flashed the EEPROM, you then need to set EE_HANDS in your config.h, rebuild the hex files and reflash.

Note that you need to program both halves, but you have the option of using different keymaps for each half. You could program the left half with a QWERTY layout and the right half with a Colemak layout using bootmagic's default layout option. Then if you connect the left half to a computer by USB the keyboard will use QWERTY and Colemak when the right half is connected.