AVR32919 Datasheet, PDF (29/41 Pages) ATMEL Corporation – 512KBytes internal flash, 256KBytes internal RAM

3.7.1.
Overview
Figure 3-16 AT32UC3C-EK Virtual Com Port Interface Logical View
The USB Virtual Com Port interface provides two features to the Atmel AT32UC3CEK kit:
• USB communication
• Power supply (see Power Supply on page 8 for a description of that feature)
The USB controller is the Atmel AT32UC3B1256. The AT32UC3B1256 comes pre-loaded with several
firmwares:
• A USB DFU Bootloader to re-program the AT32UC3B1256
• A USB CDC-USART bridge where every data character received from USB is sent to the Atmel
AT32UC3C0512C's USART2 and every character received from the AT32UC3C0512C's USART2
is sent to USB
Attention: 
Programming the AT32UC3B1256 will overwrite the default firmware.
The AT32UC3B1256 can be debugged through the JTAG interface J31 header.
The AT32UC3B1256 is connected to the AT32UC3C0512C's USART2 TX and RX pins.
Atmel AVR32919: UC3C Evaluation Kit [USER GUIDE] 29
Atmel- 32151B-UC3C-Evaluation-Kit_User Guide-05/2015