USB firmware upgrading for Atmel microcontrollers


dfu-programmer target[:usb-bus,usb-addr] command [options] [parameters]
dfu-programmer --help
dfu-programmer --targets
dfu-programmer --version


dfu-programmer is a multi-platform command line Device Firmware Upgrade (DFU) based programmer for the flash memory on Atmel AVR, AVR32, XMEGA and 8051 based microcontrollers which ship with a USB boot loader. It supports In System Programming (ISP) for developers and potentially product updates in the field. Those boot loaders are patterned after the standard USB DFU 1.0 class specification, but depend on extensions defined by Atmel to the extent that standard DFU drivers will not work.

To use it, first connect the device to be programmed and ensure that it comes up in DFU mode. The microcontrollers come up in that mode as shipped by Atmel; or they may reenter that mode after a special hardware reset. Then invoke this program to issue one or more DFU commands. You will normally need to start by issuing the "erase" command; the default security policies prevent extracting firmware, to prevent reverse engineering of what is usually proprietary code.


These chip names are used as the command line "target" parameter.

8051 based controllers:

at89c51snd1c, at89c51snd2c, at89c5130, at89c5131, at89c5132

AVR based controllers:

at90usb1287, at90usb1286, at90usb1287-4k, at90usb1286-4k, at90usb647, at90usb646, at90usb162, at90usb82, atmega32u6, atmega32u4, atmega32u2, atmega16u4, atmega16u2, atmega8u2

AVR32 based controllers:

at32uc3a0128, at32uc3a1128, at32uc3a0256, at32uc3a1256, at32uc3a0512, at32uc3a1512, at32uc3a0512es, at32uc3a1512es, at32uc3a364, at32uc3a364s, at32uc3a3128, at32uc3a3128s, at32uc3a3256, at32uc3a3256s, at32uc3a4256s, at32uc3b064, at32uc3b164, at32uc3b0128, at32uc3b1128, at32uc3b0256, at32uc3b1256, at32uc3b0256es, at32uc3b1256es, at32uc3b0512, at32uc3b1512, at32uc3c064, at32uc3c0128, at32uc3c0256, at32uc3c0512, at32uc3c164, at32uc3c1128, at32uc3c1256, at32uc3c1512, at32uc3c264, at32uc3c2128, at32uc3c2256, at32uc3c2512

XMEGA based controllers:

atxmega64a1u, atxmega128a1u, atxmega64a3u, atxmega128a3u, atxmega192a3u, atxmega256a3u, atxmega16a4u, atxmega32a4u, atxmega64a4u, atxmega128a4u, atxmega256a3bu, atxmega64b1, atxmega128b1, atxmega64b3, atxmega128b3, atxmega64c3, atxmega128c3, atxmega256c3, atxmega384c3, atxmega16c4, atxmega32c4


There are no mechanisms to implement gang programming. By default, the first device that matches the id codes for the given target is selected. Many targets share the same id codes. Accordingly, you will usually avoid connecting more than one device of a given family (AVR, XMEGA, AVR32 or 8051) at a time.

The target may be qualified with the USB bus and address number of the device you wish to program. This allows programming multiple devices of the same family at the same time.

All of these commands support the "global options". Unless you override it, commands which write to the microcontroller will perform a validation step that rereads the data which was written, compares it to the expected result, and reports any errors.

Note that unlike Atmel's BatchISP program, dfu-programmer will only perform a single operation at a time. Erasing and programming require separate commands.

configure register [--suppress-validation] data

Bootloaders for 8051 based controllers support writing certain configuration bytes.

dump [--force] [--bin] [(flash)|--user|--eeprom]

Reads the program memory in flash and output non-blank pages in ihex format to stdout. Use --force to output the entire memory and --bin for binary output. User page and eeprom are selected using --user and --eeprom.

erase [--force]

Erases all the flash memory. For AT90 and ATmega type devices a chip erase must be performed before other commands become available. Erase first checks if the memory is blank unless --force flag is set.

flash [--force] [(flash)|--user|--eeprom] [--suppress-validation] [--suppress-bootloader-mem] [--validate-first] [--ignore-outside]
[--serial=hexbytes:offset] file or STDIN

Writes flash memory. The input file (or stdin) must use the "ihex" file format convention for a memory image. --suppress-bootloader-mem ignores any data written to the bootloader memory space when flashing the device. This option is particularly useful for the AVR32 chips. The --force flag tells the program to ignore whether memory inside the program region is blank. User page and eeprom are selected using --user and --eeprom. The user space flash on AVR32 chips lies outside of the normal range of flash blocks and is designed to contain configuration parameters. Bootloader configuration uses the last 4 to 8 bytes of the user page. If this data is corrupted, the device will restart into the bootloader until valid data is used (see atmel doc7745 or doc32166). --force is always required here.

--serial provides a way to inject a serial number or other unique sequence of bytes into the memory image programmed into the device. This allows using a single .ihex file to program multiple devices, and still give each device its own unique serial number. For example, --serial=ABCDEF01:0x6000 would program the byte at 0x6000 with the hex value AB, the byte at 0x6001 with the value CD, and so on. There must be an even number of hex digits, but the sequence can be any length. The offset is assumed to be given in hex if it starts with a "0x" prefix, octal if it begins with a "0", otherwise is it assumed to be decimal.

--validate-first add a validate before writing the flash memory. If the validate succeeds (i.e. the firmware in the chip is the same as the one given as input), then no further operations are done, and the flash is reported as successful.

--ignore-outside changes the validate behavior to ignore any error outside the programming region. This can be useful for programming a single part of the chip (where errors outside region are expected) without ignoring the validate result.


Sets the security bit on AVR32 chips. This prevents the content being read back from the chip, except in the same session in which it was programmed. When the security fuse is set, almost nothing will work without first executing the erase command. The only way to clear the security fuse once set is to use a JTAG chip erase, which will also erase the bootloader.

get register

Displays various product identifier bytes.

launch [--no-reset]

Launch the application by resetting the device. The --no-reset flag can be used to launch the device without a reset (jump to the start address of the program).

Global Options


minimizes the output

--debug level

enables verbose output at the specified level

Configure Registers

The standard bootloader for 8051 based chips supports writing data bytes which are not relevant for the AVR based chips.

BSB - boot status byte
SBV - software boot vector
SSB - software security byte
EB - extra byte
HSB - hardware security byte

Get Register

bootloader-version - currently flashed bootloader version
ID1 - device boot identification 1
ID2 - device boot identification 2
manufacturer - the hardware manufacturer code
family - the product family code
product-name - the product name
product-revision - the product revision
HSB - same as the configure_register version
BSB - same as the configure_register version
SBV - same as the configure_register version
SSB - same as the configure_register version
EB - same as the configure_register version


None known.


The at90usb series chips do not make available any read/write protect flags so the dump or flash command may fail with a less than helpful error message. To remove any write or read protection from any chips, a full chip erasure is required. For AVR32 chips an erase operation over USB will remove protection until the device is rebooted. To remove the protection more permanently requires a JTAG erase (which will also erase the bootloader).

You may need to be a member of the uucp group in order to have access to the device without needing to be root.


Weston Schmidt <weston_schmidt@alumni.purdue.edu>


USB DFU Bootloader Datasheet (8051, AVR),
AVR32 UC3 USB DFU Bootloader Protocol,
FLIP USB DFU Protocol,
AVR32 UC3 USB DFU Bootloader


Copyright © 2005-2014 Weston Schmidt

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA