Microchip ATMEGA32U4-AUR, 8bit AVR Microcontroller, ATmega, 16MHz, 32 kB Flash, 44-Pin TQFP

The low-power Microchip 8-bit AVR RISC-based microcontroller featuring 32KB self-programming flash program memory, 2.5KB SRAM, 1KB EEPROM, USB 2.0 full-speed/low speed device, 12-channel 10-bit A/D-converter, and JTAG interface for on-chip-debug. The device achieves up to 16 MIPS throughput at 16 MHz. 2.7 - 5.5 Volt operation.

USB 2.0 Full-speed/Low Speed Device Module with Interrupt on Transfer Completion
Supports data transfer rates up to 12Mbit/s and 1.5Mbit/s
Endpoint 0 for Control Transfers: up to 64-bytes
Six Programmable Endpoints with IN or Out Directions and with Bulk, Interrupt or Isochronous Transfers
Configurable Endpoints size up to 256 bytes in double bank mode
Fully independent 832 bytes USB DPRAM for endpoint memory allocation
Suspend/Resume Interrupts
CPU Reset possible on USB Bus Reset detection
48MHz from PLL for Full-speed Bus Operation
USB Bus Connection/Disconnection on Microcontroller Request
Crystal-less operation for Low Speed mode