> What microcontrollers

STM32F7

* high-performance MCU with ARM Cortex-M7 core

* 32-bit ARM CPU @ 216 MHz

* 320 KB of RAM

* 512-1024 KB of Flash

* Single precision FPU and no fancy MMU

https://github.com/dart-lang/fletch

https://www.youtube.com/watch?v=Hx2iGEAvZRk

http://gotocon.com/dl/goto-cph-2015/slides/KasperLund_Intern...

Edit: Sounds like they plan to support the Arduino Due, but this is not implemented yet. They do not intend to support 8bit or 16bit MCUs.