Fill in README

Author: eproxus

README.md

@@ -1,9 +1,25 @@
-grisp_emulation
-=====
+# grisp_emulation
 
-An OTP library
+This is a hardware emulation layer for the
+[GRiSP runtime](https://github.com/grisp/grisp). With this, you can replace the
+GRiSP specific low-level drivers with a native Erlang emulation. This allows you
+to run the GRiSP runtime on a normal development computer instead of on the
+board.
 
-Build
------
+The emulation layer comes with a few different emulated Pmod drivers:
 
-    $ rebar3 compile
+* PmodACL2
+* PmodGYRO
+* PmodNAV
+
+The emulated drivers are in various states of development, ranging from just
+barely starting to a semi-full emulated state of hardware components.
+Contributions adding new drivers are welcome!
+
+It also comes with an emulation structure for changing the low-level drivers:
+
+* SPI
+* GPIO
+* I2C
+
+This is what the emulated drivers above hook into to fake actual hardware.