CircuitPython 6.2.0 Beta 4 Released! @adafruit @circuitpython

Raspberry Pi Pico RP2040 and Adafruit Feather RP2040

This release, 6.2.0-beta.4, is the fifth beta release of CircuitPython 6.2.0. Notable changes since 6.2.0-beta.3 include new RP2040 fixes and features, enhancements to bitmaptools, and turning off usb_cdc by default (it can still be enabled in a custom build). See Port status below for details on port stability for each port, and Known issues for known problems. If you find any issues with this release, please file an issue.

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 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).

Port status

CircuitPython has a number of “ports” that are the core implementation for a variety of microcontroller families. Stability varies on a per-port basis. As of this release, atmel-samd, cxd56 (Spresense), nrf, and stm for the F4 family are stable. esp32s2, raspberrypi, and stm for other STM chip families are being actively improved but may be missing functionality and have bugs. litex and mimxrt10xx are in an alpha state and will have bugs and missing functionality.

Changes since 6.2.0-beta.3

Full commit log is here.

Fixes and enhancements

  • Mark bitmaptools.arrayblit() destination as dirty. #4430. Thanks @jepler.
  • Add displayio.Palette.is_transparent(palette_index). #4426. Thanks @kmatch98.
  • Add uniform board.LED pin names for several boards. More later. #4421. Thanks @kattni.
  • Add bitmaptools.readinto() and bitmaptools.arrayblit(). #4403. Thanks @jepler.
  • Disable usb_cdc, the second USB serial port, by default. it was on by default in 6.2.0-beta.3. It is still available to use in a custom build. #4384. Thanks @dhalbert.
  • Save ~1500 bytes of firmware space via slight changes in vm execution with a minor speed penalty. #4344. Thanks @jepler.
  • Refactor displayio set_pixel for use in bitmap_tools. #4357. Thanks @kmatch98.
  • Update TinyUSB. #4327. Thanks @hathach.
  • Fix regression of TinyUSB version. #4365. Thanks @tannewt.
  • Fix incorrect 16-bit signedness in displayio.TileGrid. #4287. Thanks @deshipu.
  • Fix TileGrid.transpose_xy crash. #4331. Thanks @dhalbert.
  • Update ulab to fix matrix vetor multiplication issue. #4250. Thanks @jepler.
  • Code and documentation cleanups. #4335. #4337, #4338, #4351, #4391. Thanks @tyomitch.

Board- and port-specific changes

  • ESP32-S2
    • Fix wifi and I2C interfering with each other. #4387. Thanks @dhalbert.
    • Fix watchdog deinit(). #4325. Thanks @microDev1.
  • RP2040
    • Add displayio.ParallelBus. #4130. Thanks @gamblor21.
    • Add rotaryio. #4329. Thanks @jepler.
    • Enable audiomp3; it works at low bit rates. #4380. Thanks @jepler.
    • Lower default flash speed. #4392, #4393. Thanks @tannewt.
    • Initalize rtc with a reasonable time. #4379. Thanks @jepler.
    • Add new features to rp2pio.StateMachine. #4329. Thanks @jepler.
    • Add double reset into UF2 bootloader. #4375. Thanks @hathach.
    • Fix use of tud_disconnect(). #4327. Thanks @hathach.
    • Fix clock stretch on board.I2C(). #4390. Thanks @dhalbert.
    • Allow more than one program per PIO. #4405. Thanks @DavePutz.
  • SAMD51
    • Use SDASETUP to improve I2C rise times. #4370. Thanks @jposada and thanks @k3wals for the diagnosis.
  • Spresense
    • Minor I2C, SPI, and UART fixes. #4386, #4412. Thanks @kamtom480.
  • STM32
    • Add all modules enabled in STM32F405 to STM32F407. #4385. Thanks @hierophect.
    • Fix UART.deinit(). #4383. Thanks @hierophect.
    • Add GD25Q16C as a possible flash chip. #4356. Thanks @jerryneedell.
  • Teensy 4.0 and 4.1
    • Enable EVE. #4342. Thanks @jamesbowman.

Build and infrastructure changes

  • Run code-formatting over source code based and add to pre-commit. #4362, #4415. Thanks @microDev1 and @jepler.
  • Shrink some builds, using optimization flags. #4333. Thanks @dhalbert.
  • Avoid secondary build failure when a test fails. #4340. Thanks @jepler and thanks @microDev1 for the original inspiration PR.
  • Automatically count EXTERNAL_FLASH_DEVICES. #4358. Thanks @jepler.


  • Improve documentation for RTC, TouchIn, and analogio. #4402, #4407. Thanks @jposada2020.
  • Add README.rst link to SourceGraph, which provides searching in the circuitpython repo. #4416. Thanks @tannewt.
  • Add RP2040 port to README.rst. #4416. Thanks @tannewt.
  • Correct and enhance documentation for usb_cdc. #4359. Thanks @dhalbert.
  • Fix typos in microcontroller.nvm documentation. #4346. Thanks @jepler.
  • Translation additions and improvements. Thanks:
    • @MisterD66 (German)
    • @Edrig (French)
    • @hugodahl (French)
    • @Padanian (Italian)
    • @bergdahl (Swedish)
    • Amir Muhammad Al-Omari (Swedish)
    • @fede2cr (Spanish)
    • @jposada202020 (Spanish)
    • @wtuemura (Portuguese – Brazil)
    • @hexthat (Chinese – Pinyin)
    • Luca De Filippo (Italian)

New boards since 6.2.0-beta.3

  • Franzininho WiFi Wroom. #4347. Thanks @FBSeletronica.
  • Franzininho WiFi Wrover.#4348. Thanks @FBSeletronica.
  • Pimoroni Tiny 2040. #4228. Thanks @ZodiusInfuser.
  • Pimoroni Keybow 2040. #4228. Thanks @ZodiusInfuser.
  • Pimoroni PicoSystem. #4228. Thanks @ZodiusInfuser.
  • SparkFun MicroMod nRF52840. #4350. Thanks @nitz.
  • SparkFun Pro Micro RP2040. #4419. Thanks @spe2.

Breaking changes since 5.x

  • i2cslave is now i2cperipheral and the class in it is changed as well.
  • The stop kwarg has been removed from I2C.writeto(). If no stop is desired, then use writeto_then_readfrom.
  • The default speed of busio.I2C and board.I2C is now 100khz, not 400khz as before. Use busio.I2C to set the speed explicitly.
  • _bleio.ConnectionError has been removed. Code will now raise the native ConnectionError instead.

Known issues

  • RP2040: A few I2C devices do not work on the RP2040 with busio.I2C. Use bitbangio.I2C instead, and use bitbangio.I2C(..., probe=False) if necessary. See #4082 and #4235.
  • See for other issues.


Thank you to all who used, tested, and contributed since 6.2.0-beta.3, including @ajs256, @askpatrickw, @bergdahl, @caternuson, @danielwarnersmith, @DavePutz, @dglaude, @dhalbert, @dpgeorge, @Edrig, @falkenad, @FBSeletronica, @fede2cr, @FoamyGuy, @hathach, @hexthat, @hierophect, @hugodahl, @ismael-miguel, @jamesbowman, @jepler, @jerryneedell, @jposada202020, @kamtom480, @kattni, @kevinjwalters, @kmatch98, @ladyada, @makermelissa, @microDev1, @mintakka, @MisterD66, @nitz, @Padanian, @siehputz, @skieast, @spe2, @tannewt, @tylercrumpton, @tyomitch, @v923z, @weblate, @wtuemura, and many others on GitHub and Discord. 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) or sponsoring MicroPython on GitHub.


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.

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