This is a CDC/DFU/UF2 bootloader for nRF52 boards.
- Adafruit CLUE
- Adafruit Circuit Playground Bluefruit
- Adafruit Feather nRF52832
- Adafruit Feather nRF52840 Express
- Adafruit Feather nRF52840 Sense
- Adafruit ItsyBitsy nRF52840 Express
- Adafruit Metro nRF52840 Express
- Electronut Labs Papyr
- MakerDiary MDK nRF52840 USB Dongle
- Nordic nRF52840DK PCA10056
- Nordic nRF52840DK PCA10059 ("Dongle")
- Particle Argon
- Particle Boron
- Particle Xenon
UF2 is an easy-to-use bootloader that appears as a flash drive. You can just copy .uf2
-format
application images to the flash drive to load new firmware.
See https://github.com/Microsoft/uf2 and https://github.com/adafruit/uf2-samdx1
for more information.
adafruit-nrfutil,
a modified version of Nordic nrfutil,
is required to perform DFU.
Install python3
if it is not installed already and run this command to install adafruit-nrfutil from PyPi:
$ pip3 install --user adafruit-nrfutil
This repository depends on the following submodules:
Note that tinyusb
also includes nrfx
as a submodule, so you need
to initialize and update submodules with the `--recursive`` flag.
Clone this repo with following commands, or fork it for your own development
git clone https://github.com/adafruit/Adafruit_nRF52_Bootloader
cd Adafruit_nRF52_Bootloader
git submodule update --init --recursive
- DFU over Serial and OTA ( application, Bootloader+SD )
- Self-upgradable via Serial and OTA
- DFU using UF2 (https://github.com/Microsoft/uf2) (application only)
- Auto-enter DFU briefly on startup for DTR auto-reset trick (832 only)
There are two pins, DFU
and FRST
that bootloader will check upon reset/power:
Double Reset
Reset twice within 500 ms will enter DFU with UF2 and CDC support (only works with nRF52840)DFU = LOW
andFRST = HIGH
: Enter bootloader with UF2 and CDC supportDFU = LOW
andFRST = LOW
: Enter bootloader with OTA, to upgrade with a mobile application such as Nordic nrfConnect/ToolboxDFU = HIGH
andFRST = LOW
: Factory Reset mode: erase firmware application and its dataDFU = HIGH
andFRST = HIGH
: Go to application code if it is present, otherwise enter DFU with UF2- The
GPREGRET
register can also be set to force the bootloader can enter any of above modes (plus a CDC-only mode for Arduino).GPREGRET
is set by the application before performing a soft reset.
On the Nordic PCA10056 DK board, DFU
is connected to Button1, and FRST
is connected to Button2.
So holding down Button1 while clicking RESET will put the board into USB bootloader mode, with UF2 and CDC support.
Holding down Button2 while clicking RESET will put the board into OTA (over-the-air) bootloader mode.
On the Nordic PCA10059 Dongle board, DFU
is connected to the white button.
FRST
is connected to pin 1.10. Ground it to pull FRST
low, as if you had pushed an FRST
button.
There is an adjacent ground pad.
For other boards, please check the board definition for details.
To create your own UF2 DFU update image, simply use the Python conversion script on a .bin file or .hex file, specifying the family as 0xADA52840. If using a .bin file with the conversion script you must specify application address with the -b switch, this address depend on the SoftDevice size/version e.g S140 v6 is 0x26000
To create a UF2 image from a .bin file:
uf2conv.py firmware.bin -c -b 0x26000 -f 0xADA52840
To create a UF2 image from a .hex file:
uf2conv.py firmware.hex -c -f 0xADA52840
You can burn and/or upgrade the bootloader with either a J-link or DFU (serial) to a specific pre-built binary version without the hassle of installing a toolchain and compiling the code. This is preferred if you are not developing/customizing the bootloader. Pre-builtin binaries are available on GitHub releases
Note: The bootloader can be downgraded. Since the binary release is a merged version of both bootloader and the Nordic SoftDevice, you can freely upgrade/downgrade to any version you like.
You should only continue if you are looking to develop bootloader for your own. You must have have a J-Link available to "unbrick" your device.
Prerequisites
- ARM GCC
- Nordic's nRF5x Command Line Tools
To build:
make BOARD=feather_nrf52840_express all combinehex
To flash the bootloader with JLink:
make BOARD=feather_nrf52840_express flash
To upgrade the bootloader using DFU Serial via port /dev/ttyACM0
make BOARD=feather_nrf52840_express SERIAL=/dev/ttyACM0 dfu-flash
To flash SoftDevice (and chip erase):
make BOARD=feather_nrf52840_express sd
To erase all of flash:
make BOARD=feather_nrf52840_express erase
For the list of supported boards, run make
without BOARD=
:
$ make
You must provide a BOARD parameter with 'BOARD='
Supported boards are: feather_nrf52840_express feather_nrf52840_express pca10056
Makefile:90: *** BOARD not defined. Stop
If you get the following error ...
$ make BOARD=feather_nrf52840_express all
Compiling file: main.c
/bin/sh: /usr/bin/arm-none-eabi-gcc: No such file or directory
make: *** [_build/main.o] Error 127
... you may need to pass the location of the GCC ARM toolchain binaries to make
using
the variable GNU_INSTALL_ROOT
as below:
$ make GNU_INSTALL_ROOT=/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/ BOARD=feather_nrf52832 all
Please note that the path needs a trailing path separator (a /
)
Make sure that mergehex
is available from the command-line. This binary is
part of Nordic's nRF5x Command Line Tools.
Make sure that nrfjprog
is available from the command-line. This binary is
part of Nordic's nRF5x Command Line Tools.
On POSIX-type systems you can temporarily add the path to nrfjprog
via a
variation on the following command:
$ export PATH=$PATH:/location/of/nRF5x-Command-Line-Tools_9_7_2_OSX/nrfjprog
For easier debugging you can also use SES.
The project file is located at src/segger/Adafruit_nRF52_Bootloader.emProject
.
Note: SES only flashes the bootloader when you click download, not the SoftDevice. You need to flash the SoftDevice beforehand if you haven't already done so. As mentioned above do something like:
make BOARD=feather_nrf52840_express sd