Espruino

Espruino was created by Gordon Williams in 2012 as an attempt to make microcontroller development truly multiplatform.

[3][4] Though initially not open-source, the Espruino firmware was offered as a free download for STM32 microcontrollers.

[5] It was made open-source in 2013 after a successful Kickstarter campaign[6] for a development board running the software.

[11][12] There is a large body of reference material for Espruino including over 100 tutorials[13] as well as the book Making Things Smart[14] which contains a selection of hardware projects that can be created with Espruino-based microcontrollers.

To achieve maximal memory efficiency, Espruino executes code from source directly inside the parser, without the use of an Abstract Syntax Tree or intermediate bytecode.

The Original Espruino, the first official development board.
The Original Espruino, the first official development board, offers 44 GPIO pins, Micro SD card support, a Micro USB interface and controllable LEDs and buttons. It has 256 kiB of flash and 48 kiB of RAM and runs on a 72 MHz ARM Cortex M3 processor.