.. only:: esp32 .. note:: Device Firmware Upgrade through USB is not supported with ESP32 chips.
Device Firmware Upgrade (DFU) is a mechanism for upgrading the firmware of devices through Universal Serial Bus (USB). DFU is supported by ESP32-S2 chips. The necessary connections for the USB peripheral are shown in the following table.
GPIO | USB |
---|---|
20 | D+ (green) |
19 | D- (white) |
GND | GND (black) |
+5V | +5V (red) |
Note
The ESP32-S2 chip needs to be in bootloader mode for the detection as a DFU device and flashing. This can be achieved by pulling GPIO0 down (e.g. pressing the BOOT button), pulsing RESET down for a moment and releasing GPIO0.
Warning
Some cables are wired up with non-standard colors and some drivers are able to work with swapped D+ and D- connections. Please try to swap the cables connecting to D+ and D- if your device is not detected.
The software requirements of DFU are included in :ref:`get-started-get-prerequisites` of the Getting Started Guide.
Section :ref:`api_guide_dfu_build` describes how to build firmware for DFU with ESP-IDF and Section :ref:`api_guide_dfu_flash` deals with flashing the firmware.
The DFU image can be created by running:
idf.py dfu
which creates dfu.bin
in the build directory.
Note
Don't forget to set the target chip by idf.py set-target
before running idf.py dfu
. Otherwise, you might
create an image for a different chip or receive an error message something like unknown target 'dfu'
.
The DFU image is downloaded into the chip by running:
idf.py dfu-flash
which relies on dfu-util. Please see :ref:`get-started-get-prerequisites` for
installing dfu-util
. dfu-util
needs additional setup for :ref:`api_guide_dfu_flash_win` or setting up an
:ref:`api_guide_dfu_flash_udev`. Mac OS users should be able to use dfu-util
without further setup.
If there are more boards with the same chip connected then idf.py dfu-list
can be used to list the available
devices, for example:
Found Runtime: [303a:0002] ver=0723, devnum=4, cfg=1, intf=2, path="1-10", alt=0, name="UNKNOWN", serial="0" Found Runtime: [303a:0002] ver=0723, devnum=6, cfg=1, intf=2, path="1-2", alt=0, name="UNKNOWN", serial="0"
Consequently, the desired device can be selected for flashing by the --path
argument. For example, the devices
listed above can be flashed individually by the following commands:
idf.py dfu-flash --path 1-10 idf.py dfu-flash --path 1-2
Note
The vendor and product identificators are set based on the selected chip target by the idf.py set-target
command and it is not selectable during the idf.py dfu-flash
call.
See :ref:`api_guide_dfu_flash_errors` and their solutions.
udev is a device manager for the Linux kernel. It allows us to run dfu-util
(and idf.py dfu-flash
) without
sudo
for gaining access to the chip.
Create file /etc/udev/rules.d/40-dfuse.rules
with the following content:
SUBSYSTEMS=="usb", ATTRS{idVendor}=="303a", ATTRS{idProduct}=="00??", GROUP="plugdev", MODE="0666"
Note
Please check the output of command groups
. The user has to be a member of the GROUP specified above. You may
use some other existing group for this purpose (e.g. uucp on some systems instead of plugdev) or create a new
group for this purpose.
Restart your computer so the previous setting could take into affect or run sudo udevadm trigger
to force
manually udev to trigger your new rule.
dfu-util
uses libusb to access the device. You have to register on Windows the device with the WinUSB driver.
Please see the libusb wiki for more
details.
The drivers can be installed by the Zadig tool. Please make sure that the device is in download mode before running the tool and that it detects the ESP32-S2 device before installing the drivers. The Zadig tool might detect several USB interfaces of ESP32-S2. Please install the WinUSB driver for only that interface for which there is no driver installed (probably it is Interface 2) and don't re-install the driver for the other interface.
Warning
The manual installation of the driver in Device Manager of Windows is not recommended because the flashing might not work properly.
dfu-util: command not found
might indicate that the tool hasn't been installed or is not available from the terminal. An easy way of checking the tool is runningdfu-util --version
. Please see :ref:`get-started-get-prerequisites` for installingdfu-util
.- The reason for
No DFU capable USB device available
could be that the USB driver wasn't properly installed on Windows (see :ref:`api_guide_dfu_flash_win`), udev rule was not setup on Linux (see :ref:`api_guide_dfu_flash_udev`) or the device isn't in bootloader mode. - Flashing with
dfu-util
on Windows fails on the first attempt with errorLost device after RESET?
. Please retry the flashing and it should succeed the next time.