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CircuitPython 2.3.0 Released!

Get the 2.3.0 release on GitHub!


The 2.3.0 CircuitPython release fixes a longstanding issue of CIRCUITPY sometimes being erased when applying power or when batteries run down. It also adds the CircuitPlayground and HID libraries as frozen libraries on the Circuit Playground Express build. And finally, if CIRCUITPY becomes partially corrupted, you can now use storage.clear_filesystem() to erase and reformat it, and reset the board.


Power-on CIRCUITPY corruption fix

CircuitPython writes version information to boot_out.txt when it starts from a hard reset or power on. It also writes whatever (or, etc.) prints to boot_out.txt. If power failed while boot_out.txt was being written, CIRCUITPY could become severely corrupted. When power returned, CircuitPython would erase and reformat CIRCUITPY to fix the corruption. Several things were done to ameliorate this problem:

  1. Do not rewrite boot_out.txt if the version information in it will not change and there is no
  2. If the version information has changed, or there is a file, wait 1.5 seconds to ensure power is stable before starting to write boot_out.txt and run
  3. Raise the “brownout” voltage below which CircuitPython refuses to run from 1.7V to 2.8V. This ensures all chips on the board have proper voltage to run.

Additional frozen libraries added to CircuitPython image for Circuit Playground Express

The CircuitPlayground (aka Express or cpx) library and the HID librariy have been added as frozen libraries to the Circuit Playground Express firmware image. The CircuitPlayground library provides easy access to the built-in sensors and peripherals on the Circuit Playground Express (CPX) board. Using the frozen versions of these libraries can save RAM and allow you to run larger programs. Remove the versions in the lib/ directory if you want to use the frozen versions. (Or change sys.path to put .frozen first.)


Sometimes CIRCUITPY becomes partially corrupted, but not badly enough so that it is automatically reformatted. You can now use erase.filesystem() to reformat easily and quickly, without having to use a special erase .uf2 file and then reload CircuitPython. In the REPL, just do:

import storage

This will erase and reformat CIRCUITPY, and reset the board.

Other changes

The _stage module now uses 16-bit coordinates to support larger screens. Thanks @deshipu!

The esp8266 build now uses the latest version of the SDK toolchain. Thanks @jepler!


Thanks to @dhalbert@tannewt@kattni@jepler@deshipu@ladyada, and @croadfeldt (who helped greatly with testing the power fixes) for help with this release! Join us on the Discord chat to collaborate.


Documentation is available in

Here are all the changes since 2.2.4.

This release is based on MicroPython 1.9.2. Support upstream MicroPython by purchasing a PyBoard(from Adafruit here).


Check out this guide for info on common problems with CircuitPython. If you are still having, then post to the Adafruit Support Forums and join Discord.


The 2.2.0 mpy-cross executables in this release work fine with 2.3.0.

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