Getting a hex file onto a 32U4

Other Hardware 3rd Party Boards
1

I was hoping someone could point me in the right direction.
I have an Atmega32U4 board I want to upload a hex file to. I am lost as to how to do it. I read some stuff about using an AVR programmer and compiling a 'make' file.

Better yet let me give you the full story. I wan't to make a Christmas present for a friend. Get an original SNES controller and use a micro-controller to convert it to USB as a gamepad. A la instructable.
I did it on a Teensy 2.0 and it worked. I want to upload the hex file to a Pololu A-Star 32U4 Micro because it's cheaper and I want to re-purpose the Teensy.

At my disposal I have the Teensy 2.0, Pololu A-Star 32U4 Micro and an Arduino UNO R3 (ATMEGA328P in DIP package with ATMEGA16U2 usb chip [16U2 firmware upgraded for UnoJoy project])

2

There is a 6-pin connector location on the long end opposite the USB. This is the ISP connections. Use an Arduino running the ArduinoISP sketch or another similar sketch such as the one from Nick Gammond. Set the board type to a 32U4 board and burn the boot loader. You may need to install a hardware board to get exactly the boot loader and fuse configuration you wish.

Ex: Sparkfun Pro Micro

Nick's site: Learn Here

Ray