Adafruit ItsyBitsy RP2040

Adafruit ItsyBitsy RP2040 offers an ultra-fast dual Cortex M0+ processor running at 125MHz in a small, powerful microcontroller board. The ItsyBitsy RP2040 is 1.4" long by 0.7" wide, has six power pins, 23 digital GPIO pins (4 of which can be analog in and 16 x PWM out) with 8MB of FLASH and 264KB of SRAM.

The Adafruit ItsyBitsy RP2040 features the RP2040 chip with the clock speed of the M4 (SAMD51) and two cores equivalent to M0 (SAMD21). The device provides many peripherals, including two I²C controllers, two SPI controllers, and two UARTs multiplexed across the GPIO. The device has 16 PWM channels, and each pin has a channel that can be set to (and on the pinout).

Features

Same size and form-factor as the rest of the ItsyBitsy family and nearly-identical pinout
Measures 1.4" x 0.7" x 0.2" (36mm x 18mm x 4mm) without headers soldered-in
RP2040 32-bit Cortex M0+ dual core running at ~125MHz @ 3.3V logic and power
264KB RAM
8MB SPI FLASH chip for storing files and CircuitPython/MicroPython code storage, no EEPROM
23 x GPIO pins with following capabilities:
Four 12 bit ADCs (one more than Pico)
Two I²C, Two SPI and two UART peripherals, we label one for the 'main' interface in standard ItsyBitsy locations
16 x PWM outputs - for servos, LEDs, etc
The 10 digital 'non-ADC/non-peripheral' GPIO are consecutive for maximum PIO compatibility
Pin #13 red LED for general purpose blinking

RGB NeoPixel with power pin on GPIO so you can depower it for low power usages
Both Reset button and Bootloader select button for quick restarts (no unplugging-replugging to relaunch code)
3.3V regulator with 500mA peak current output
3.3V Power/enable pin
Power with either USB or external output (such as a battery) - it'll automatically switch over
Broken-out SWD pins for debug access
12MHz crystal for perfect timing.
Special Vhigh output pin gives you the higher voltage from VBAT or VUSB, for driving NeoPixels, servos, and other 5V-logic devices, digital 5 level-shifted output for high-voltage logic level output
USB Micro B connector lets you access built-in ROM USB bootloader and serial port debugging