esp-idf/docs/en/api-guides/dfu.rst
2020-05-13 15:40:55 +02:00

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***********************************************
Device Firmware Upgrade through USB
***********************************************
.. 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.
.. _api_guide_dfu_build:
Building the DFU Image
======================
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'``.
.. _api_guide_dfu_flash:
Flashing the Chip with the DFU Image
====================================
The DFU image is downloaded into the chip by running::
idf.py dfu-flash
which relies on `dfu-util <http://dfu-util.sourceforge.net/>`_. 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.
See :ref:`api_guide_dfu_flash_errors` and their solutions.
.. _api_guide_dfu_flash_udev:
udev rule (Linux only)
----------------------
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.
.. _api_guide_dfu_flash_win:
USB drivers (Windows only)
--------------------------
``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 <https://github.com/libusb/libusb/wiki/Windows#How_to_use_libusb_on_Windows>`_ for more
details.
The drivers can be installed by the `Zadig tool <https://zadig.akeo.ie/>`_. 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.
.. _api_guide_dfu_flash_errors:
Common errors and known issues
------------------------------
- ``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 running ``dfu-util --version``. Please see :ref:`get-started-get-prerequisites` for
installing ``dfu-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 error ``Lost device after RESET?``. Please
retry the flashing and it should succeed the next time.