THIS WAS THE HARDEST PART OF GETTING EVERYTHING RUNNING AND I SPENT 3+ DAYS WORKING THE ISSUE

YOU WILL NEED A KEYBOARD

• NOTE 1: we're going to do everything command line, but if you need retroarch menu,
  • it's <SCROLL + F1>
• NOTE 2: We need this because by default, Missile Command and Tempest are looking for LIGHTGUN, not mouse, so we need to enable the mouse.

Score 1 for Gemini.. ChatGPT just fell apart.

Before we start, and before firing up the game,

• we bring up the game in our MAME menu,
• then long press Button 1 to bring up a menu.
• Move down to “Advanced Game Options”.
  • Emulator will be LIBRETRO:MAME for Phoenix and Missle Command,
  • and LIBRETRO: MAME078PLUS for Centipede.

The system sees every USB device (Keyboard, PS3 controller, Xinmotec, Trackball) and gives it a “Mouse Index” number.

• Command: cat /proc/bus/input/devices
• Discovery: You found the Cypress Semiconductor (the trackball) and saw Handlers=mouse0.
• Result: This told us your magic number is Index 0.

The Emulator Core (MAME) has to be told that it is allowed to use a mouse at all.

• Location: /userdata/system/configs/retroarch/config/MAME/missile.opt
• Key Setting: mame_mouse_enable = “enabled”
• Result: This turned on the “ears” of the emulator so it could hear mouse signals.

Because the menu wasn't saving, we manually created a “Game Override” file. This tells RetroArch exactly which hardware to plug into the “Player 1” slot.

• Creation: We created a new text file at: /userdata/system/configs/retroarch/config/MAME/missile.cfg
• The Code: You added these two critical lines:
  • input_player1_mouse_index = “0” (Points to the Trackball)
  • input_libretro_device_p1 = “3” (Tells MAME to treat Player 1 as a “Mouse” device)

Tempest uses a spinner, but in MAME, a spinner is just the X-axis (left/right) of a mouse. To fix Tempest without doing all that work again:

• Navigate to the same folder: /userdata/system/configs/retroarch/config/MAME/
  • Copy missile.cfg and Paste it as tempest.cfg.
  • Copy missile.opt and Paste it as tempest.opt.

Launch Tempest. It will now use the same “Index 0” logic.

Summary Table for Future Reference