This part is a kind of semiconductor called ATXMEGA128A3U.
Function of this product has 8/16-bit Atmel XMEGA A3U Microcontroller.
Manufacturers : Atmel
Image and pinout :
Some of the text within the PDF file :
8/16-bit Atmel XMEGA A3U Microcontroller ATxmega256A3U / ATxmega192A3U / ATxmega128A3U / ATxmega64A3U Features High-performance, low-power Atmel® AVR® XMEGA® 8/16-bit Microcontroller Nonvolatile program and data memories 64K - 256KBytes of in-system self-programmable flash 4K - 8KBytes boot section 2K - 4KBytes EEPROM 4K - 16KBytes internal SRAM Peripheral features Four-channel DMA controller Eight-channel event system Seven 16-bit timer/counters Four timer/counters with four output compare or input capture channels Three timer/counters with two output compare or input capture channels High resolution extension on all timer/counters Advanced waveform extension (AWeX) on one timer/counter One USB device int [ ... ]