BeBoPr for CNC - modmaker/BeBoPr GitHub Wiki
The BeBoPr can be used as a general purpose BeagleBone interface-board with analog inputs, digital inputs, (PWM) outputs, and stepper motor controllers.
LinuxCNC
Besides running the 3D-printer code from the BeBoPr software repository, the BeBoPr cape can now also be used to interface a BeagleBone (running LinuxCNC) with for example a milling machine, lathe, laser cutter, high-speed router, or other similar machine.
LinuxCNC has a long history (formerly known as EMC2) of being used for serious machine control with a wide range of machines in various toolshops all over the world. People use it to retrofit cheap bench mills, but also many really big industrial machines.
The BeagleBone port uses both realtime kernel (xenomai) and a PRU to generate accurate stepping signals. Because LinuxCNC was made for real CNC work, it can also do curves (G2/G3), radius compensation (G41/G42) and much, much more. The real-time kernel makes it better fit for machine control.
Michael Haberler and Charles Steinkuehler have ported LinuxCNC to the BeagleBone / BeBoPr combination and Charles made an easy to install package called MachineKit based on Robert C Nelson's excellent Debian 7.0.0 (wheezy) distribution .
MachineKit
MachineKit contains two configurations: One for the original BeagleBone and BeBoPr, and another one for the 'Bridged' BeBoPr. The latter is 100% compatible with the BeagleBone Black and allows use of the eMMC and/or HDMI interfaces. The Bridge also works with the LVDS cape to connect an LCD panel, as can be seen here.
Stepper signals
The logic analyzer on the photo captures the stepper signals from the BeBoPr. The images below show some snapshots of these signals.
BeagleBone of choice
As the PRU code in MachineKit is not using the PRU outputs for the stepper signals, it is also possible to use an original BeagleBone (White) in combination with BeBoPr and LinuxCNC.
However, if you want to run completely stand-alone (with monitor, mouse and keyboard), your best choice is to use a BeagleBone Black with a BeBoPr-Bridge on the BeBoPr. This provides all the features from the BeagleBone Black (on-board HDMI, LVDS cape, eMMC and audio) in combination with accurate stepper signals from the PRUSS.