How to program GamerKey V1 via ISP
Updated: Nov 30, 2020

STEP 1: Download and install Arduino MiniCore core library:
Download the Arduino software, Install the Arduino software, following the instructions for Windows, Mac OS X or Linux
Follow these instructions to install MiniCore: In Arduino, you can install the MiniCore support using the built-in boards manager,
Open the preferences dialog in the Arduino software.
Find the “Additional Boards Manager URLs” field near the bottom of the dialog.

Paste the following URL into the field https://mcudude.github.io/MiniCore/package_MCUdude_MiniCore_index.json
Click the OK button to save your updated preferences.
Open the boards manager in the “Tools > Board” menu.

Select “MiniCore by MCUdude” and click “Install”.
Close the boards manager. You should now see an entry for MiniCore in the “Tools > Board” menu.
STEP 2: Turning the Arduino board into a ISP programmer:
We’re going to use the Arduino board to program GamerKey. First, we’ll need to turn the Arduino board into an ISP
Open the ArduinoISP sketch from the examples menu.

Select the board (on Tools > Board menu) and serial port (on Tools > Serial Port) that correspond to your Arduino board.

Upload the ArduinoISP sketch to the Arduino UNO board.
STEP 3: Connecting the Arduino UNO board to GamerKey
NOTE: You don’t need to solder the connector to GamerKey, you can just insert the 6 pin header on GamerKey and hold gently bent during uploading of program.
We’ll connect the Arduino UNO board to the GamerKey as shown in the following diagram:


STEP 4: Burn Bootloader on GamerKey:
We can use the Arduino as an ISP to upload the bootloader to GamerKey:
NOTE: GamerKey comes with bootloader installed already.

Select “ATmega328” from the Tools > Board menu
Select “8Mhz (internal)” from Tools > Clock
Select “BOD: disabled” from Tools > BOD
Select “LTO disabled” from Tools > Compiler LTO
Select “328P / 328PA” from Tools > Variant
Select “No bootloader” from Tools > Bootloader
Leave the serial port set to your Arduino UNO board
Select “Arduino as ISP” from the Tools > Programmer menu.

Be sure that you have removed the battery from GamerKey.
Burn Bootloader from the Tools menu.

You should see “Done burning bootloader.” in the Arduino software and no error messages. Now you can upload the sketch.
STEP 5: Upload Sketch to GamerKey:
we can use the Arduino as an ISP to upload a program to GamerKey
Download the Game Sketch from here
Open the Game sketch with Arduino IDE
Check the Board (ATmega328), the Clock (8Mhz (internal)), the BOD (BOD: disabled), the Compiler LTO (LTO disabled), the Variant (328P / 328PA), the Bootloader (No bootloader) from Tools > Board menu and leave the serial port set to that of your Arduino UNO board.
Select “Arduino as ISP” from the Tools > Programmer menu.
Be sure that you have removed the battery from GamerKey.
Upload the sketch.
You should see “Done uploading.” in the Arduino software and no error messages.
Insert the battery on GamerKey and start to play!
Note: Repeat only step 5 every time you want to upload a different sketch on GamerKey. It’s not necessary to burn the bootloader every time. You just need to burn it the first time.