The CircuitPython 4.0.0 Beta 3 release is available here: https://github.com/adafruit/circuitpyth … 0.0-beta.3.

This is a beta build of 4.0.0. There are still issues to fix before stable and the new APIs may evolve a bit more. Please use the latest 3.x stable release when first starting with CircuitPython. It is stable.

When you find a bug please check the current known issues and file an issue if something isn’t already known.

4.0.0

4.0.0 is the latest major revision of CircuitPython. It features: – a port to the Nordic nRF52840 microcontroller, including support as a BLE beacon or peripheral ( bleio ) – extensive new support for pixel-based displays ( displayio ) – USB MIDI support – messages translated into multiple languages

Installation

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).

Most builds are available as both UF2 and bin files here along with test builds.

Check for length too long on Python sequence multiply, thanks to @tannewt .

. rotaryio added to nrf port, thanks to @nickzoic .

added to nrf port, thanks to . ENOSPC error now has numan-readable text, thanks to @cpforbes .

error now has numan-readable text, thanks to . USB MIDI fixes, thanks to @cpforbes .

. Set __file__ for main source code file, thanks to @cpforbes .

for main source code file, thanks to . Space-saving and build fixes, thanks to @debrouxl , for use with a specialized build for a TI calculator accessory.

, for use with a specialized build for a TI calculator accessory. German translation improvements, thanks to @Tasm-Devil .

. Rework of translation builds and output, to reduce merge difficulties, thanks to @tannewt .

. Many displayio additions, improvements, and fixes, thanks to @tannewt .

additions, improvements, and fixes, thanks to . displayio and PyPortal board fixes and improvements, thanks to @TG-Techie .

and PyPortal board fixes and improvements, thanks to . Fix atmel-samd UART implementation, thanks to @dhalbert .

UART implementation, thanks to . Additional re (was ure ) functionality, thanks to @notro .

(was ) functionality, thanks to . Entering safe mode via slow double click fixed on SAMD51, thanks to @tannewt .

. The long list of links to CircuitPython driver documentation is now a part of the CircuitPython Bundle instead of being part of the circuitpython repo. Thanks to @sommersoft .

. Build options were extensively refactored, allowing features to be turned on and off more easily. The atmel-samd and nrf ports were also made much more similar, and share more common settings now. Thanks to @dhalbert .

and ports were also made much more similar, and share more common settings now. Thanks to . Support print(..., flush=True) , thanks to @tannewt .

, thanks to . Add support for 1-bit (monochrome), 8-bit (indexed and grayscale), 16-bit (565), and 32-bit (ARGB) pixel sizes in displayio.OnDiskBitmap , thanks to @siddacious .

, thanks to . bleio bug fixes, thanks to @dhalbert .

bug fixes, thanks to . Ability to allow filesystem writes from both USB and internal CircuitPython (dangerous!), thanks to @tannewt , with inspiration from @ladyada .

, with inspiration from . Refactoring of timer code into `samd-peripherals, thanks to @sommersoft .

. Add .height and .width properties to Display , thanks to @penguindustin .

and properties to , thanks to . ‘displayio` refresh fixes, thanks to @dhalbert .

. PWMOut fixes on atmel-samd, thanks to @dhalbert , and thanks to @kevinjwalters for discovering the problem and testing the fix.

fixes on atmel-samd, thanks to , and thanks to for discovering the problem and testing the fix. frequencyio.FrequencyIn frequency measurement capability on atmel-samd ports, thanks to @sommersoft .

New Boards

SAM32. Thanks to @maholli .

Breaking Changes from 3.x!

ure , ujson , and uerrno renamed to re , json , and errno to reflect that they are subsets of the CPython library modules. Thanks to @dhalbert .

, , and renamed to , , and to reflect that they are subsets of the CPython library modules. Thanks to . busio.UART breaking changes to match PySerial. Thanks to @dhalbert

breaking changes to match PySerial. Thanks to busio.UART constructor timeout parameter is now in seconds instead of milliseconds.

UART.readinto(buf) now does not allow an optional length parameter UART.readinto(buf, len) .

. UART.write(…) no longer allows strings to be written. The bytes written must be bytes or bytearray or an array.array.

framebuf has been removed. displayio is its replacement, and will be enhanced after 4.0 to include framebuf ‘s functionality. Thanks to @tannewt .

has been removed. is its replacement, and will be enhanced after 4.0 to include ‘s functionality. Thanks to . Improve struct compatibility with CPython by enforcing stricter types. This may break your code! Thanks to @dhalbert .

Thanks

Thank you to all who used, tested, contributed, helped out, and participated on GitHub and/or Discord: @adafruit, @anecdata, @arofarn, @arturo182, @ATMakersBill, @brennen, @brentru, @bwshockley, @C47D, @CarlFK, @carlosperate, @caternuson, @CedarGroveStudios, @chalei, @charlesbunaford, @cpforbes, @dastels, @deshipu, @dhalbert, @dsiee, @edspark, @eighthree, @furlaneto, @gcvasconcelos, @glennrub, @gpshead, @hathach, @iraytrace, @Jahor, @jasonp, @jepler, @Jay Doscher, @jerryneedell, @jimblom, @JohnPark, @JoshuaLowe1002, @uanita, @kattni, @kevinjwalters, @klardotsh, @Klowner, @ladyada, @larsks, @madbodger, @maholli, @Makdaam, @MakerMelissa, @MattyT, @mchobby, @microbuilder, @MikeBarela, @Mr. Certainly, @mrmcwethy, @nickzoic, @notro, @oldcrow, @penguindustin, @PhredFL, @platipo, @Retoc, @rhooper, @sabas1080, @sajattack, @sajattack, @saspa, @schmarty, @Senuros, @ShawnHymel, @siddacious, @sommersoft, @SouthernDragon, @TangoJuliett, @tannewt, @Tasm-Devil, @TG-Techie, @uhrheber, @urish, @vgoodwinv, @xpecex, @yeyeto2788, and surely more we have missed. Join us on the Discord chat to collaborate.

Documentation

Documentation is available in readthedocs.io.

Here are all the changes since 4.0.0-beta.2. Here are all the changes since 3.1.2.

This release is based on [MicroPython 1.9.4 @25ae98f](https://github.com/micropython/micropython/commit/25ae98f07cb3c4488cb955403dfe56b8bb8db6f0). Support upstream MicroPython by purchasing a PyBoard (from Adafruit here).

Troubleshooting

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.