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+This project bring CNC control for ARM based Linux boards like Raspberry Pi.
+Typically there is no way to control stepper motors from Linux runtime
+environment due to the lack of real time GPIO control. Even kernel based
+modules can not guarantee precise control of pulses for steppers. There is
+always way out. DMA(Direct Memory Access) is a separated hardware module which
+provides high precision for GPIO outputs. This module can copy bytes which
+represent GPIO states from RAM buffer directly to GPIO with some clock based
+on main chip internal oscillator without using CPU's cores. Using such approach
+this project generates impulses for moving stepper motors and that is very
+precise way regardless CPU load and OS time jitter.  
+This approach also allows to use Python language for this project. Typically,
+Python is not good choice for real time application, but since project just
+needs to set up DMA buffers and hardware will do the rest, Python become the
+perfect choice for easy development of this project.
+
+Video demo - [YouTube video](https://youtu.be/vcedo59raS4)
+
+#Current command support
+G0, G1, G4, G20, G21, G28, G90, G91, G92, M2, M3, M5, M30  
+Commands can be easily added, see [gmachine.py](./gmachine.py) file.
+
+#Config
+All config is stored in [config.py](./config.py) and contains hardware properties, limitations
+and pin names for hardware control.
+
+#Hardware
+Currently, this project supports Raspberry Pi 1-3. But there is a way to add new boards.
+See [hal.py](./hal.py) file.
+
+#Performance notice
+Pure Python interpreter wouldn't provide great performance for high speed machines.
+Overspeeding setting causes motors mispulses and probably lose of trajectory. According 
+to my tests, Raspberry Pi 2 can handle axises with 400 pulses on mm with top velocity ~800 mm 
+per min. There is always way out! :) Use JIT Python implementation like PyPy. RPi2 can handle
+up to 18000 mm per minute on the machine with 80 steps per millimeter motors with PyPy.  
+_Note: Raspbian has outdated PyPy version in repositories(v4.0). Moreover v4.0 has issue with
+`mmap` module implementation. Use PyPy v5.0+, download it for your OS from
+[here](https://pypy.org/download.html)._  
+PyPy installation:
+```bash
+wget wget https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.7.1-linux-armhf-raspbian.tar.bz2
+sudo mkdir /opt/pypy
+sudo tar xvf pypy2-v5.7.1-linux-armhf-raspbian.tar.bz2 --directory /opt/pypy/ --strip-components=1
+sudo ln -s /opt/pypy/bin/pypy /usr/local/bin/pypy
+```
+
+#Dependencies
+Nothing. Just pure Python code.
+
+#GCode simulation
+Just a link to a nice web software for gcode files emulation (very helpful for manual creating of
+gcode files): [https://nraynaud.github.io/webgcode/](https://nraynaud.github.io/webgcode/)
+
+#License
+see [LICENSE](./LICENSE) file.
+
+#Author
+Nikolay Khabarov
+