SparkFun Pro nRF52840 Mini - Bluetooth Development Board

    ARM Cortex-M4 CPU with floating point unit (FPU)
        1MB internal Flash -- For all of your program, SoftDevice, and file-storage needs!
        256kB internal RAM -- For your stack and heap storage.
    Integrated 2.4GHz radio with support for:
        Bluetooth Low Energy (BLE) -- With peripheral and/or central BLE device support
        Bluetooth 5 -- Mesh Bluetooth!
        ANT -- If you want to turn the device into a heart-rate or exercise monitor.
        Nordic's proprietary RF protocol -- If you want to communicate, securely, with other Nordic devices.
    Every I/O peripheral you could need
        USB -- Turn your nRF52840 into a USB mass-storage device, use a CDC (USB serial) interface, and more. This is a big add compared to the nRF52832!
        UART -- Serial interfaces with support for hardware flow-control if desired.
        I2C -- Everyone's favorite 2-wire bi-directional bus interface
        SPI -- If you prefer the 3+-wire serial interface
        Analog-to-digital converters (ADC) -- Eight pins on the nRF52840 Mini Breakout support analog inputs
        PWM -- Timer support on any pin means PWM support for driving LEDs or servo motors.
        Real-time clock (RTC) -- Keep close track of seconds and milliseconds, also supports timed deep-sleep features.
    Peripheral-multiplexing -- (Nearly) any pin can support any of the above features.