Seeed Studio XIAO RP2040 Microcontroller, with Dual-Core ARM Cortex M0+ Processor, Supports Arduino, MicroPython and CircuitPython with Rich Interfaces.

Tons of processing power in a package the size of your thumb. So tiny that any USB cable plugged into it has to be secured as it weighs more than the MCU itself. Barely uses any power even while operating at full tilt, and absolutely just barely sips on a battery while in standby mode. You’d think that the GPIO would leave something to be desired, but given its size I wouldn’t say that’s much of an issue. If you need more pins, get an expansion board or use a different model. Super useful if you’re trying to shrink down your projects - pairs well with displays and other components from Adafruit, Waveshare, etc.

GPIOの数が少なくていい時はとても重宝します。I2CやUARTで外部モジュールを繋げば、小さなボードでも多彩なことに使えています。またオンボードのLEDとしてRGBのほかNeoPixelまでひとつ付いてるので、インジケーターとして便利に使えます。 開発はArduino IDEでやっています。他のRP2040ボード（RasPi Pico等）と違って、ケーブル抜き差しやBootボタンの操作をせずとも書き込みができるので、プログラムをちょこちょこ手直ししながらの実験がとてもスムーズにできます。

It is painful one to avoid at all costs

Updated review. Found more information and I'm quite pleased with the Xiao Rp2040. So far it works with SSD1306 Oled display. See attached video of 3D plotter I wrote. Using the U8g2 library configured for SSD1306. I also tried an SH1106 display. the 1306 driver in the u8g2 library works with minor glitches, the 1106 config doesn't work at all. I'm trying to find libraries for use with ST7735 and 7789 displays. I also wrote a sketch that generates random color on the internal RGB LED, when fades from one color to the next. Doesn't require any external connections. That LED is bright! It's a work in progress of course.

特に使いづらさなどもなくよかったです。