Or alternatively press and hold A+B+C during the Universe Bios loading screen
Which allows you to open a menu to change to US region + AES system all from your controller / joystick. Do general bios configuration (Difficulty settings, freeplay, etc), as well as the Jukebox player that lets you listen to music and sound effects from the game.
Also you can press Start + Select / Coin simultaneous during the game to bring up this menu
Which allows you to reset the game or access a cheat database
In fact this is required to properly play Samurai Shodown V Special in AES mode because one of the cheats fixes the finishing moves and audio to properly play in AES mode.
It's one way to configure stuff with a controller without needing to change the modes each time with the emulators on settings.
The Universe Bios makes things convenient in that regard. (Of course it needs to be enabled prior before hand)