unupingu / ucnc

µCNC - A universal CNC firmware for microcontrollers

µCNC

µCNC - A universal CNC firmware for microcontrollers

About µCNC

Heavily inspired by the by Grbl and LinuxCNC, µCNC started to take shape in the second half of 2019 in an attempt to come out with a G-Code interpreter/controller software/firmware that is both compact and powerful as Grbl and flexible and modular as LinuxCNC, with the following goals in mind:

1. µCNC is written in C (GNU99 compliant). This gives the advantage of being supported for a large number of CPU/MCU and compilers available.
2. Modular library based:
   • Independent hardware. All MCU/hardware operations are written in a single translation unit that acts like a standardized HAL interface, leaving the CNC controlling code independent of the MCU architecture has long has it has the necessary abilities to execute code and respond to interrupts in a predictable. Porting µCNC for a different MCU should be fairly straight forward.
   • Independent kinematics. Another dimension of the HAL is the possibility of defining how the translation between machine coordinates and the motions is translated back and forth. This should theoretically allow µCNC to be easily adaptable to several types of machines like cartesian, corexy, deltas and others. µCNC supports up to 6 axis.
3. Compatible with already existing tools and software for Grbl. There is no point in trying to reinvent the wheel (the hole wheel at least :-P). For that reason µCNC (tries) to use the exact same protocol has Grbl. This allows it to easily integrate with Grbl ecosystem.

Supporting the project

µCNC is a completely free software. It took me a considerable amount of hours and effort to develop and debug so any help is appreciated. Building docs, testing and debugging, whatever. Also if you really like it and want help me keep the project running, you can help me to buy more equipment or simply buy me a coffee or two ;-)

Current µCNC status

µCNC current version is v1.1.0. This update brought a significant amount of new features and bug fixes. Among the list of new features is now possible to:

• Configurable backlash compensation
• Configurable axis skew compensation
• Alternative new planner strategy (linear actuator driven for high inertia machines)
• Dynamic step spreading algorithm (similar to Grbl's AMASS) to reduce vibrations caused by steppers at slower step rates
• HAL for STM32F1 boards now available

G-Codes support

µCNC for now supports most of the RS274NGC v3:

List of Supported G-Codes since µCNC 1.0.0-beta.2:
  - Non-Modal Commands: G4, G10*, G28, G30, G53, G92, G92.1, G92.2, G92.3
  - Motion Modes: G0, G1, G2, G3, G38.2, G38.3, G38.4, G38.5, G80
  - Feed Rate Modes: G93, G94
  - Unit Modes: G20, G21
  - Distance Modes: G90, G91
  - Plane Select Modes: G17, G18, G19
  - Tool Length Offset Modes: G43.1 G49
  - Cutter Compensation Modes: G40
  - Coordinate System Modes: G54, G55, G56, G57, G58, G59, G59.1, G59.2, G59.3
  - Control Modes: G61, G61.1, G64
  - Program Flow: M2, M30(same has M2)
  - Coolant Control: M7, M8, M9
  - Spindle Control: M3, M4, M5
  - Valid Non-Command Words: A, B, C, F, I, J, K, L, N, P, R, S, T, X, Y, Z
  - Valid Non-Command Words: E (used by 3D printing firmwares like [Marlin](https://github.com/MarlinFirmware/Marlin)) (currently not used)

  _* also G10 L2 P28 and P30 to set homming coordinates_

TODO List of G-Codes in µCNC future releases:

• Program Flow: M0, M1
• PID control

µCNC capabilities

µCNC currently supports up to (depending on the MCU/board capabilities):

• 6 independent axis
• 8* stepper step/dir drivers (6 steppers + 2 extra that can be configured to mirror 2 of the other 6 for dual drive axis)
• 9* limit switches (6 limit switch (one per axis) plus 3 optional second axis X, Y or Z support dual endstops) (interrupt driven)
• 1 probe switch (interrupt driven)
• 1 feed hold input (interrupt driven)
• 1 cycle start/resume input (interrupt driven)
• 1 emergency stop (interrupt driven)
• 1 door open switch (interrupt driven)
• 16 pwm outputs
• 16 analog inputs
• 16 generic digital inputs
• 16 generic digital outputs

µCNC with a configuration similar to Grbl is be able to keep up to 30Khz step rate for a 3 axis machine on an Arduino Uno at 16Mhz. (the stated rate depends on the lenght of the segments too, since many short length segments don't allow full speed to be achieved)

Current µCNC supported hardware

µCNC initial development was done both around Arduino UNO board just like GRBL. But µCNC can also be installed in other AVR boards like Arduino Mega (for Ramps), or similar boards (like Rambo). With v1.1.0 STM32F10x was added.

I used several UNO emulators but debugging was not easy. So a kind of virtual board (Windows PC) was created to test µCNC core code independently. It can run on:

• Arduino UNO
• Arduino MEGA
• STM32F1 Blue Pill
• Windows PC (used for simulation only - ISR on Windows doesn't allow to use it a real alternative)

In the future µCNC will most probably be extended to:

• Microchip PIC18F
• ARM
• Old PC with a RT OS???
• Other??

Building µCNC

For building µCNC go ahead to the mcus folder of the target MCU and follow the instructions specific to your device.