Work in progress (w.i.p.) to adapt a Gameport Gamepad with a custom two wire vendor protocol to a Nintendo Switch Bluetooth Gamepad. This project builds on all what has previously been done to adapt a Gamecube Controller to Nintendo Switch Bluetooth.

Original project there: https://github.com/NathanReeves/BlueCubeMod (the fork was done from a project that was adapted to a more recent ESP-IDF version). Thanks to all the effort from various people that has lead to that previous project.

The following picture shows the Gamepad in question. What is not seen on the backside are two digital and two analog shoulder/trigger buttons on each side.

• Linux Kernel Driver for Gravis GrIP protocol devices - most probably including the Gamepad at hand: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/input/joystick/grip.c
• References/Gravis_XT_Gamepad.jpg: The Gamepad I have here in front of me. It is NOT the USB version (which had USB Data lines on two of the Gameport pins, and a simple passive adapter would be enough.)
• References/Gravis_XT_idle_8MHz-sampled.sr: PulseView file, Logic Analyzer Measurements of the two relevant data pins of the Gamepad
• Forum post discussing the Gamepad and Kernel Driver, but with no proper conclusion: https://www.avrfreaks.net/forum/interpreting-serial-data-gravis

[x] Successfully compile existing project (BlueCubeModv2) - works with ESP-IDF stable, v4.4 https://docs.espressif.com/projects/esp-idf/en/v4.4/esp32/get-started/index.html

[x] Get information on Gravis Xterminator Gamepad protocol

[x] Decode Gravis Xterminator Protocol successfully on ESP32

[ ] Integrate into BlueCubeModv2

[ ] Have fun on Nintendo Switch with a decades old Gamepad

[ ] Properly integrate ESP32 board / Battery into the Xterminator Gamepad - 5V is needed for Gamepad and input protection for the 3.3V ESP32 pins are needed (not really 5V tolerant). Buck/Boost Battery circuit is needed.

[ ] If needed: design custom PCB for better integration into the Gamepad

[ ] Future (new project): Look into a Gravis GrIP joystick to USB Mod for PC? I still have a Firebird II around...