Adafruit has begun sales of its fastest CircuitPython-compatible development board yet, the Adafruit STM32F405 Feather Express which runs the popular programming environment at 168MHz.
The compact STM32F405 Feather Express board runs at 168MHz. (📷: Adafruit)
Unveiled earlier this month and now on sale both through Adafruit itself and its international reseller community, the Adafruit STM32F405 Feather Express takes the breadboard-friendly Feather form factor and adds an STMicroelectronics STM32F405 32-bit Arm Cortex-M4 processor running at 168MHz, 1MB of flash memory, a 2MB SPI flash module, on-board NeoPixel indicator, and a Qwiiic/STEMMA-QT compatible connector for solderless hardware interfacing over I2C.
The Feather board breaks out the STM32F405’s various pins, including I2C, UART, analogue-to-digital converters (ADCs), digital-to-analogue converters (DACs), and general-purpose input/output (GPIO), all of which use 3.3V logic but are 5V-safe. In another departure from the norm, the board also uses USB Type-C for data and power — making it the first Adafruit Feather board to make the switch – while a microSD socket with SDIO compatibility is included at the bottom as well as a connector and integrated charging circuitry for an optional lithium-polymer battery.
There are a handful of caveats to use of the new board, however. The CircuitPython port is under active development, and cannot yet support DisplayIO or SDIO SD cards; the board can be programmed using the Arduino IDE, but lacks an auto-reset bootloader necessitating manual boot-mode toggling and resetting; and while the board boasts “very solid” MicroPython support, Adafruit doesn’t provide compatible sensor libraries.
The board includes USB Type-C, a first for a Feather. (📷: Adafruit)
Hardware compatibility with Adafruit’s FeatherWings add-ons, meanwhile, is claimed to be good — only the RFM69/RFM9x libraries failed to operate.
More information on the board can be found on Adafruit’s learning portal.