USB Function Microcontroller.
Features:

• AT90USB1287
  • 128-Kbyte self-programming Flash Program Memory
  • USB Device & OTG
• AT90USB1286
  • 128-Kbyte self-programming Flash Program Memory
  • USB Device only
• AT90USB647
  • 64-Kbyte self-programming Flash Program Memory
  • USB Device & OTG
• AT90USB646
  • 64-Kbyte self-programming Flash Program Memory
  • USB Device only
• 8-Kbyte SRAM, 4-Kbyte EEPROM
• 8 Channel 10-bit A/D-converter
• JTAG interface for on-chip-debug
• Up to 16 MIPS throughput at 16 MHz
• 2.7 - 5.5 Volt operation.