Bare-Metal Raspberry Pi port #3522
This pull requests contains mainly a Makefile and start-code for a bare-metal port of Micropython to the Raspberry Pi along with driver-code for the UART-interface to receive any output from the device. It does not contain additional modules and does not feature any sort of command prompt.
This port works on the Raspberry Pi Zero (tested) and should also work on the Raspberry Pi 1. It will however probably not work out-of-the-box on the Raspberry Pi 2 or 3, as they feature a different processor.
If you want to read more, I wrote a term paper  about porting Micropython to bare-metal Raspberry Pi (and adding modules to it).