Only grab one if you have a use for it with something else as there is every chance it won't work with the mini.
My own Atari style 9pin to USB adapter didn't work with the mini, it's just a simple plug'n play for Windows XP or above and requires no additional software to make it work. Windows own controller calibration software sees it just fine but again, it does not work with the mini...
[ 40.436476] input: hexagons.de Retro-Joystick as /devices/platform/sw-ohci.1/usb3/3-1/3-1:1.0/input/input4
[ 40.450802] generic-usb 0003:16C0:27DC.0004: input: USB HID v1.01 Joystick [hexagons.de Retro-Joystick] on usb-sw-ohci-1/input0
[ 40.479585] input: hexagons.de Retro-Joystick as /devices/platform/sw-ohci.1/usb3/3-1/3-1:1.1/input/input5
[ 40.483812] generic-usb 0003:16C0:27DC.0005: input: USB HID v1.01 Joystick [hexagons.de Retro-Joystick] on usb-sw-ohci-1/input1
03000000c0160000dc27000001010000 for Gamecontollerdb
Works together with a the64 Joystick connected to Port 1 and the Adapter connected to Port 2 (tested a Quickshot II Turbo on left DB9) Since you have only on Button, you definetely need a the64 joystick connected to jump between the Games and Carousel.