The Microchip ATmega16U2 CMOS 8-bit microcontroller is based the AVR enhanced RISC architecture. It operates on 2.7V to 5.5V voltage supply. The AVR core combines a rich instruction set with 32 general purpose working registers. It features 16K bytes of in-system programmable flash with read-while-write capabilities, 512 Bytes EEPROM, 512 SRAM, 22 general purpose I/O lines, 32 general purpose working registers, two flexible Timer/Counters with compare modes and PWM, one USART, a programmable Watchdog Timer with Internal Oscillator, an SPI serial port, debug wire interface, also used for accessing the On-chip Debug system and programming and five software selectable power saving modes. The Idle mode stops the CPU while allowing the SRAM, Timer/Counters, SPI port, and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. In Standby mode, the Crystal/Resonator oscillator is running while the rest of the device is sleeping.

Up to 16 MIPS throughput at 16 Mhz
Programming lock for software security
Microcontroller reset on USB Bus reset without detach
USB Bus disconnection on microcontroller request
Master/Slave SPI Serial Interface
Programmable watchdog timer with separate on-chip oscillator
Power-On reset and programmable brown-out detection
Internal calibrated oscillator
External and internal interrupt sources
QFN32 (5x5mm) / TQFP32 packages