Atari Flashback Controller Teardown

Recently, I disassembled an Atari Flashback controller to see if it could be easily interfaced to an arduino for Pickin' Duino.

Once the case is open, you can easily see the side buttons are implemented with membrane switches, as is the joystick, and as are the front switches.

The board appears to be using some sort of clocked serial interface, probably SPI related.

I was hoping that the 9-pin interface was just a switch array, but there's a IC under an epoxy blob. It should be possible to learn the protocol with an oscilloscope.