FEATHER-M0-Bootloader-UF2
UF2 Bootloader Details
 |
This is an information page for advanced users who are curious how we get code from your computer into your Express board! |
Adafruit Express and Gemma/Trinket M0 boards feature an improved bootloader that makes it easier than ever to flash different code onto the microcontroller. This bootloader makes it easy to switch between Microsoft MakeCode, CircuitPython and Arduino.
Instead of needing drivers or a separate program for flashing (say, bossac, jlink or avrdude), one can simply drag a file onto a removable drive.
The format of the file is a little special. Due to 'operating system woes' you cannot just drag a binary or hex file (trust us, we tried it, it isn't cross-platform compatible). Instead, the format of the file has extra information to help the bootloader know where the data goes. The format is called UF2 (USB Flashing Format). Microsoft MakeCode generates UF2s for flashing and CircuitPython releases are also available as UF2. You can also create your own UF2s from binary files using uf2tool, available here.
The bootloader is also BOSSA compatible, so it can be used with the Arduino IDE which expects a BOSSA bootloader on ATSAMD-based boards
For more information about UF2, you can read a bunch more at the MakeCode blog, then check out the UF2 file format specification. Visit Adafruit's fork of the Microsoft UF2-samd bootloader GitHub repository for source code and releases of pre-built bootloaders.
|
The bootloader is not needed when changing your CircuitPython code. Its only needed when upgrading the CircuitPython core or changing between CircuitPython, Arduino and Microsoft MakeCode. |
Activer le mode Booloader
The first step to loading new code onto your board is triggering the bootloader. It is easily done by double tapping the reset button. Once the bootloader is active you will see the small red LED fade in and out and a new drive will appear on your computer with a name ending in BOOT. For example, feathers show up as FEATHERBOOT, while the new CircuitPlayground shows up as CPLAYBOOT, Trinket M0 will show up as TRINKETBOOT, and Gemma M0 will show up as GEMMABOOT
Furthermore, when the bootloader is active, it will change the color of one or more onboard neopixels to indicate the connection status, red for disconnected and green for connected. If the board is plugged in but still showing that its disconnected, try a different USB cable. Some cables only provide power with no communication.
For example, here is a Feather M0 Express running a colorful Neopixel swirl. When the reset button is double clicked (about half second between each click) the NeoPixel will stay green to let you know the bootloader is active. When the reset button is clicked once, the 'user program' (NeoPixel color swirl) restarts.
Crédit: AdaFruit Industries www.adafruit.com
If the bootloader couldn't start, you will get a red NeoPixel LED.
That could mean that your USB cable is no good, it isn't connected to a computer, or maybe the drivers could not enumerate. Try a new USB cable first. Then try another port on your computer!
Crédit: AdaFruit Industries www.adafruit.com
Once the bootloader is running, check your computer. You should see a USB Disk drive...
Crédit: AdaFruit Industries www.adafruit.com
Once the bootloader is successfully connected you can open the drive and browse the virtual filesystem. This isn't the same filesystem as you use with CircuitPython or Arduino. It should have three files:
- CURRENT.UF2 - The current contents of the microcontroller flash.
- INDEX.HTM - Links to Microsoft MakeCode.
- INFO_UF2.TXT - Includes bootloader version info. Please include it on bug reports.
Crédit: AdaFruit Industries www.adafruit.com
Utiliser le Bootloader Mass Storage
To flash something new, simply drag any UF2 onto the drive. After the file is finished copying, the bootloader will automatically restart. This usually causes a warning about an unsafe eject of the drive. However, its not a problem. The bootloader knows when everything is copied successfully.
Crédit: AdaFruit Industries www.adafruit.com
You may get an alert from the OS that the file is being copied without it's properties. You can just click Yes .
Crédit: AdaFruit Industries www.adafruit.com
You may also get get a complaint that the drive was ejected without warning. Don't worry about this. The drive only ejects once the bootloader has verified and completed the process of writing the new code
Utiliser le Bootloader BOSSA
As mentioned before, the bootloader is also compatible with BOSSA, which is the standard method of updating boards when in the Arduino IDE. It is a command-line tool that can be used in any operating system. We won't cover the full use of the bossac tool, suffice to say it can do quite a bit! More information is available at ShumaTech.
Pilotes pour Windows 7
If you are running Windows 7 (or, goodness, something earlier?) You will need a Serial Port driver file. Windows 10 users do not need this so skip this step.
You can download our full driver package here:
Download and run the installer. We recommend just selecting all the serial port drivers available (no harm to do so) and installing them.
Crédit: AdaFruit Industries www.adafruit.com
Verifying Serial Port in Device Manager
If you're running Windows, its a good idea to verify the device showed up. Open your Device Manager from the control panel and look under Ports (COM & LPT) for a device called Feather M0 or Circuit Playground or whatever!
Crédit: AdaFruit Industries www.adafruit.com
If you see something like this, it means you did not install the drivers. Go back and try again, then remove and re-plug the USB cable for your board
Crédit: AdaFruit Industries www.adafruit.com
Running bossac on the command line
If you are using the Arduino IDE, this step is not required. But sometimes you want to read/write custom binary files, say for loading CircuitPython or your own code. We recommend using bossac v 1.7.0 (or greater), which has been tested. The Arduino branch is most recommended.
You can download the latest builds here. The mingw32 version is for Windows, apple-darwin for Mac OSX and various linux options for Linux. Once downloaded, extract the files from the zip and open the command line to the directory with bossac
For example here's the command line you probably want to run:
bossac -e -w -v -R ~/Downloads/adafruit-circuitpython-feather_m0_express-0.9.3.bin
This will -erase the chip, -write the given file, -verify the write and -Reset the board. After reset, CircuitPython should be running. Express boards may cause a warning of an early eject of a USB drive but just ignore it. Nothing important was being written to the drive. A hard power-reset is also recommended after bossac, just in case.
Crédit: AdaFruit Industries www.adafruit.com
Faire une mise-à-jour du bootloader
The UF2 bootloader is a new bootloader, and while we've done a ton of testing, it may contain bugs. Usually these bugs effect reliability rather than fully preventing the bootloader from working. If the bootloader is flaky then you can try updating the bootloader itself to potentially improve reliability.
Updating the bootloader is as easy as flashing CircuitPython, Arduino or MakeCode. Simply enter the bootloader as above and then drag the update bootloader uf2 file below. This uf2 contains a program which will unlock the bootloader section, update the bootloader, and re-lock it. It will overwrite your existing code such as CircuitPython or Arduino so make sure everything is backed up!
After the file is copied over, the bootloader will be updated and appear again. The INFO_UF2.TXT file should show the newer version number inside.
For example:
UF2 Bootloader v1.20.0 SFHR Model: Adafruit Feather M0 Board-ID: SAMD21G18A-Feather-v0
Lastly, reload your code from Arduino or MakeCode or flash the latest CircuitPython core.
The latest updaters for various boards:
Eliminer les popups Windows
If you do a lot of development on Windows with the UF2 bootloader, you may get annoyed by the constant "Hey you inserted a drive what do you want to do" pop-ups.
Toutes les images ci-dessous sont créditées à Adafruit Industries - All images here under are credited to Adafruit Industries
|
Go to the Control Panel. Click on the Hardware and Sound header |
|
Click on the Autoplay header |
|
Uncheck the box at the top, labeled Use Autoplay for all devices |
Faire votre propre UF2
Making your own UF2 is easy! All you need is a .bin file of a program you wish to flash and the Python conversion script. Make sure that your program was compiled to start at 0x2000 (8k) because the bootloader takes the first 8k. CircuitPython's linker script is an example on how to do that.
Once you have a .bin file, you simply need to run the Python conversion script over it. Here is an example from the directory with uf2conv.py:
uf2conv.py -c -o build-circuitplayground_express/revg.uf2 build-circuitplayground_express/revg.bin
This will produce a revg.uf2 file in the same directory as the source revg.bin. The uf2 can then be flashed in the same way as above.
Source: Adafruit Feather M0 Express - Designed for CircuitPython créé par LadyAda, Tony DiCola, Scorr Shawcroft, Dan Halbert pour AdaFruit Industries. Crédit AdaFruit Industries
Traduit par Meurisse D. pour MCHobby.be
Traduit avec l'autorisation d'AdaFruit Industries - Translated with the permission from Adafruit Industries - www.adafruit.com
Toute référence, mention ou extrait de cette traduction doit être explicitement accompagné du texte suivant : « Traduction par MCHobby (www.MCHobby.be) - Vente de kit et composants » avec un lien vers la source (donc cette page) et ce quelque soit le média utilisé.
L'utilisation commercial de la traduction (texte) et/ou réalisation, même partielle, pourrait être soumis à redevance. Dans tous les cas de figures, vous devez également obtenir l'accord du(des) détenteur initial des droits. Celui de MC Hobby s'arrêtant au travail de traduction proprement dit.