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For Beaglebone Black: A G-code interpreter and stepmotor controller for crazy fast coordinated moves of up to 8 steppers. Uses the Programmable Realtime Unit (PRU).

beagleg.org/

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GPL-3.0 license
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BeagleG

License: GPL v3   Ubuntu Build

Step-motor controller for CNC-like devices (or 3D printers) using the PRU (Programmable Realtime Unit) of the Beaglebone Black to create precisely timed and fast stepper-pulses for acceleration and travel. (And with fast, we're talking up to 1Mhz fast. For 8 motors in parallel. In a controlled move (G1). So this is not a limit in real-world applications).

Works with a cape designed by the author (the BUMPS cape), but also provides relatively easy adaption to new hardware (currently: support for CRAMPS). See hardware subdirectory.

This was one of my very early tests: First Test

The {accl-,decel-}eration and travel motion profile is entirely created within the PRU from parameters sent by the host CPU decoupled via a ring-buffer. The BeagleBone main CPU prepares the data, such as parsing the G-Code and doing travel planning, while all the real-time critical parts are done in the PRU. The host CPU typically needs less than 1% CPU-time doing everything else (and there is no need for a real-time kernel).

The main machine-control program is parsing G-Code, extracting axes moves and enqueues them to the realtime unit. It can receive G-Code from a file or socket (you can just telnet to it for an interactive session, how cool is that?).

Install

For detailed system configuration and building the machine-control binary, see INSTALL.md.

Before you can use beagleg and get meaningful outputs on the GPIO pins, two things are required on a fresh Beaglebone installation (we recommend the IoT image).

Enable PRU

To enable the PRU the way we use it, we need to /boot/uEnv.txt and enable the correct uboot_overlay_pru line.

We need to disable the line containing PRU-RPROC (add a # in front) and enable the line containing the PRU-UIO (remove # in front).

###pru_uio (4.14.x-ti, 4.19.x-ti & mainline/bone kernel)
uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo

Reboot.

Enable Output Pins for your board

The GPIO pins used for each hardware This is how you initialize the pins if you use the BUMPS board:

/opt/source/bb.org-overlays/tools/beaglebone-universal-io/config-pin -f hardware/BUMPS/bumps.pins

See the Hardware page for more boards.

Machine control binary

To control a machine with G-Code, use the machine-control binary. This either takes a filename or a TCP port to listen on.