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CircuitPython 5.4.0 Beta 0 released!
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CircuitPython 5.4.0 Beta 0 released!

by tannewt on Mon May 11, 2020 10:01 pm

From the GitHub release page:
This is the first beta release of CircuitPython 5.4.0. This release adds basic lower power support when in time.sleep(). The lower power work changed time keeping and may have introduced bugs. Please use 5.3.0 if you need a stable version of CircuitPython.

Download from
Downloads are available from! The site makes it easy to select the correct file and language for your board. The downloads page is here. Downloads are no longer available from the GitHub release pages because of the large number of files for each release.

To install follow the instructions in our new Welcome to CircuitPython! guide. To install the latest libraries, see this page in that guide.

Try the latest version of the Mu editor for creating and editing your CircuitPython programs and for easy access to the CircuitPython serial connection (the REPL).

New features and improvements since 5.3.0
  • Add sleep support while time.sleep() on ports except CXD56 and LiteX. Thanks to @tannewt
  • ujson.load can now use mp_stream objects like busio.UART. Thanks to @WarriorOfWire
  • rgbmatrix now supported on STM32F4. Thanks to @jepler
  • aesio added for C level AES. Thanks to @xobs
  • displayio enabled on STM32H7 boards. Thanks to @hierophect
  • One directional SPI now supported on IMX RT. Thanks to @hierophect and @arturo182
  • Added empty Swedish translations. (Try our new Weblate site to add and improve translations.) Thanks @jepler
  • _pixelbuf.colorwheel color order fixed. Thanks to @kattni
  • PacketBuffer reliability improved. Thanks to @dhalbert
    • packet_size is deprecated in favor of incoming_packet_length.
    • outpoing_packet_length added so calling code can split input appropriately.
  • ulab updated. Removed from espruino_pico and espruino_pico due to space. Thanks to @v923z and @jepler
    • Adds
  • os and pulseio enabled on STM32F7. Thanks to @k0d
  • Pinout of Teknikio Bluebird pinout updated for newer rev. Thanks to @JoeBakalor
  • Itaca uChip now has .bin files as well as .uf2. Thanks to @mew-cx
  • STATUS2 is no longer read for SPI Flashes with single status bytes. Thanks to @bd34n
  • Doc fixes. Thanks to @rhooper and @spkuehl
Full commit log is here.

New boards since 5.3.0
Known Issues
  • displayio operations that read from an SD card (e.g., OnDiskBitmap) will interfere with other SD card operations and can cause lockup. To work around this problem, do not read or write files on the SD while the display is updating, and vice versa.
  • See for other issues.
Thank you to all who used, tested, contributed since 5.3.0, helped out, and participated on GitHub and/or Discord, including @arturo182, @bd34n, @DavePutz, @dhalbert, @hathach, @hierophect, @jepler, @JoeBakalor, @kattni, @k0d, @ladyada, @mew-cx, @rhooper, @spkuehl, @Teknikio, @theacodes, @TG-Techie, @v923z, @WarriorOfWire, @xiongyihui, @xobs and surely more we have missed. Join us on the Discord chat to collaborate.

Documentation is available in

This release is based on MicroPython 1.9.4 @25ae98f. Support upstream MicroPython by purchasing a PyBoard (from Adafruit here).

One important feature of CircuitPython is translated control and error messages. With the help of fellow open source project Weblate, we're making it even easier to add or improve translations. Sign in with an existing account such as Github, Google or Facebook and start contributing through a simple web interface. No forks or pull requests needed!

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

Builds are no longer stored as assets on this release page, because there are too many of them. Please see the Download from section above.

Posts: 2020
Joined: Thu Oct 06, 2016 8:48 pm

Please be positive and constructive with your questions and comments.