atmega32u4-dat

datasheet link

USB 2.0 Full-speed/Low Speed Device Module with Interrupt on Transfer Completion

• – Complies fully with Universal Serial Bus Specification Rev 2.0
• – 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

ref

• AVR-dat