What a sweet cake! Or is it...a QT Py? This diminutive dev board comes with our favorite Lil chip, the SAMD21 (as well known in our GEMMA M0 and Trinket M0 boards). This time it comes with our favorite plug - the STEMMA QT, a chainable I2C connector that can be used with any of our STEMMA QT sensors and accessories. OLEDs! Inertial units Sensors a plenty. All plug and play thanks to innovative chainable design: SparkFun Qwiic compatible STEMMA QT plugs for the I2C bus, so you dont even have to solder! Simply plug in a compatible cable and attach it to your MCU of choice, and youre ready to load some software and measure some light. Use all SparkFun Qwiic boards! Seeed Grove I2C boards also work with this adapter cable. Pinout and mold are Xiao compatible, with castellated pads, so you can solder it flat onto a circuit board. In addition to the QT port, we also have an RGB NeoPixel (with controllable power pin added for very low power use) and a reset button (ideal for restarting your program or entering the bootloader); Arduino runs like a dream and can be used for basic CircuitPython projects. For advanced applications such as datalogging or file storage, solder a SOIC SPI flash chip to the bottom pads, same size, form factor, and pin-out as Seed Xiao USB Type-C connector - If you only have Micro B cable, this adapter comes in handy. ATSAMD21E18 32-bit Cortex M0+ - 48 MHz 32 bit processor with 256 KB flash and 32 KB RAM native USB supported by any operating system - can be used in Arduino or CircuitPython as a USB serial console, MIDI, keyboard/mouse HID, even a small drive for storing Python scripts . Can be used with Arduino IDE or CircuitPython Built in RGB NeoPixel LED 11 GPIO pins: true analog output on an I/O pin, can be used to play 10-bit audio clips in Arduino (CircuitPython does not have memory for audio clips) 9 x 12-bit analog inputs (SDA/SCL do not have analog inputs), 1 or AREF A1 9 x PWM-Output