CircuitPython 7.3.0 Release Candidate 0 Released! @circuitpython

From the GitHub release page:

This is CircuitPython 7.3.0-rc.0, the first release candidate for CircuitPython 7.3.0. It is considered stable, and is available as a release candidate for testing before the final release of 7.3.0.

Notable changes to 7.3.0 since 7.2.5

  • Experimental mDNS support.
  • USB to to Serial/JTAG support for REPL on appropriate boards.
  • Initial experimental USB host support.
  • Merge MicroPython 1.18 changes.
  • Preliminary zlib module support. gzip module will be added later.
  • RP2040 PIO: Background write to a PIO state machine. Looping is possible.
  • RP2040 PIO: wrap and wrap_target support.
  • keypad: scan keystates immediately on creation.
  • Improve NeoPixel timings on many ports, to handle a wider range of devices.
  • Add floppyio, used in conjunction with a library.
  • Allow TileGrid bitmap to be changed.
  • Module support matrix includes frozen modules for each board.

Download from

Firmware downloads are available from the downloads page on The site makes it easy to select the correct file and language for your board.


To install follow the instructions in the 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).


Documentation is available in

Port status

CircuitPython has a number of “ports” that are the core implementations for different microcontroller families. Stability varies on a per-port basis. As of this release, these ports are consider stable:

  • atmel-samd: Microchip SAMD21, SAMx5x
  • cxd56: Sony Spresense
  • espressif: Espressif ESP32-S2
  • nrf: Nordic nRF52840, nRF52833
  • raspberrypi: Raspberry Pi RP2040
  • stm: ST STM32F4 chip family

These ports are considered alpha and will have bugs and missing functionality:

  • broadcom: Raspberry Pi boards such as RPi 4, RPi Zero 2W
  • espressif: ESP32-S3, ESP32-C3
  • litex: fomu
  • mimxrt10xx: NXP i.MX RT10xxx
  • stm: ST non-STM32F4 chip families

Changes since 7.3.0-beta.2

Fixes and enhancements

  • Update frozen modules. #6398. Thanks @dhalbert.
  • Fix auto-reload during BLE workflow. #6389, #6380, #6377. Thanks @tannewt.
  • Correct two errno messages. #6376. Thanks @dhalbert.
  • Fix usb_hid usage range error message. #6370. Thanks @wlcx.
  • microcontroller.Pin is now hashable. #6342. Thanks @dhalbert.
  • Validate color_depth is 1 on SH1107 displays. #6338. Thanks @jepler.
  • Shrink flash storage for many built-in properties. #6337. Thanks @jepler.
  • Fix PulseIn.popleft() buffer over-read. #6318. Thanks @mwisslead.

Port and board-specific changes



  • Fix for long delays between I2C transactions. #6366. Thanks @o-marshmallow for ESP-IDF fix and @dhalbert.
  • Fix returned DigitalInOut.pull values. #6354. Thanks @dhalbert.


  • Allow any GPIO pin for rs485_dir pin. #6328. Thanks @KurtE.



  • Fix buffer filling issue for PulseIn. #6361. Thanks @mwisslead.
  • Improve rp2pio.StateMachine. #6360. Thanks @jepler.
  • Allow any GPIO pin for rs485_dir pin. #6330. Thanks @KurtE.


  • Avoid compiling parts of samd module for boards that did not use it. #6350. Thanks @dhalbert.
  • Preserve tick functionality across VM instantiations. #6321. Thanks @dhalbert.


Individual boards

  • Adafruit Metro M4 AirLift Lite: add board.LED. #6343. Thanks @dhalbert.
  • Adafruit PyRuler: add board.LED. #6343. Thanks @dhalbert.
  • Adafruit QT Py ESP32-C3: fix duplicate #include. #6352. Thanks @askpatrickw.
  • Adafruit QT Py ESP32-S2 No PSRAM: fix board.NEOPIXEL and board.NEOPIXEL_POWER pins. #6352. Thanks @todbot.
  • Adafruit Qt Py ESP32-S3: correct SPI pins. #6393. Thanks @todbot.
  • Pimoroni Servo 2040: add board.NEOPIXEL. #6339. Thanks @jepler.
  • SparkFun Thing Plus RP2040: fix pin mapping. #6358. Thanks @dupontgu.

Documentation changes

  • List frozen modules for each board in support matrix in readthedocs. #6400, 6396, #6288. Thanks @Neradoc.
  • Additional module documentation and builtin exceptions, including Guide links. #6391, #6353, #6341. Thanks @tekktrik.
  • Add memory usage recommendations to MP3Decoder. #6329. Thanks @tekktrik.
  • Document watchdog.WatchDogTimeout. #6324. Thanks #tekktrik.

Build and infrastructure changes

  • make help now includes make fetch-submodules. #6385. Thanks @TG-Techie.
  • Build website pull request for with adafruit-adabot user. #6344. Thanks @dhalbert.
  • List frozen modules in the support matrix. #6288. Thanks @Neradoc.

Translation additions and improvements

Thanks for translations:

  • @bergdahl (Swedish)
  • @wtuemura (Portugese – Brazil)

New boards since 7.3.0-beta.2

  • Ctryon Maker Feather AIoT S3. #6382. Thanks @CytronTechnologies.
  • Lilygo TTGO T-OI Plus ESP32C3. #6387. Thanks @SimonVail.
  • Pewpew LCD. #6331. Thanks @pypewpew (@deshipu).
  • ZRichard RP2.65-F. #6334. Thanks @BigTuna94.

Known issues

  • See for other issues, including issues still to be addressed for:


Thank you to all who used, tested, and contributed since 7.3.0-beta.2, including the contributors above, and many others on GitHub and Discord. Join us on the Discord chat to collaborate.

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