This is a small electronic board with Xilinx Spartan 3 FPGA connected directly to the Beagleboard-xM 2x14 expansion connector. Designed to mount back-to-back. This cape is conceived as an addon I/O board with mid-level on-board FPGA and a small microcontroller to support reconfigurable digital software defined radio, antenna control, robotics, motor control, and other modules.
https://www.indiegogo.com/projects/beagleboard-xm-cape-the-two-dawn-board-radio/