Features Pre-programmed bootloader for AVR UC3 A0, A1, A3, B0, B1 series USB DFU Bootloaders up to version 1.0.3 USB Protocol Based on the USB Device Firmware Upgrade (DFU) Class Autobaud (8-, 12- and 16-MHz Crystal on Osc0) In-System Programming (ISP) Configurable I/O Start Conditions (default is pressing the joystick on EVK1100 and EVK1101, SW2 button on EVK1104). Protected by 8-Bit CRC Can Be Forced by the General-Purpose Fuses Read/Write Flash on-Chip Memories AVR 32 32-bit Read Device ID Full-Chip Erase Microcontroller Start Application Command AVR UC3 A0, A1, A3, B0, B1 USB DFU Bootloader up to version 1.0.3 7745CAVR3205/091. Description AVR UC3 devices with the USB feature are shipped with a USB bootloader. This USB bootloader allows to perform In-System Programming (ISP) from a USB host control- ler without removing the part from the system, without a pre-programmed application and without any external programming interface other than USB. There is one bootloader compiled for each AVR UC3 serie. The hardware I/O conditions used to request the start of the ISP are also specific to each serie. This document describes the USB bootloader functionalities and its usage in various contexts. 2. Related Parts This documentation applies to the following AVR UC3 parts: AT32UC3A0512 AT32UC3A0256 AT32UC3A0128 AT32UC3A1512 AT32UC3A1256 AT32UC3A1128 AT32UC3A3256 AT32UC3A3256S AT32UC3A3128 AT32UC3A3128S AT32UC3A364 AT32UC3A364S AT32UC3B0512 AT32UC3B0256 AT32UC3B0128 AT32UC3B064 AT32UC3B1512 AT32UC3B1256 AT32UC3B1128 AT32UC3B164 Note: This is the list of AVR UC3 devices shipped with the pre-programmed USB DFU Bootloader version 1.0.z. For an accurate Bootloader version per AVR UC3 devices overview, refer to the table Pre-programmed Bootloader Versions in AVR UC3 Devices in section 8.2. The bootloader is compiled for each AVR UC3 A0, A1, A3, B0, B1 series because of differences in the MCU peripheral memory map. The functionalities are the same between all series. 3. Related Items AVR UC3 A0,A1 Series Datasheet: