grbl-LPC-CoreXY/README.md
Sonny Jeon 71f333ddca Settings refactoring. Bug fixes. Misc new features.
This is likely the last major change to the v0.9 code base before push
to master. Only two minor things remain on the agenda (CoreXY support,
force clear EEPROM, and an extremely low federate bug).

- NEW! Grbl is now compile-able and may be flashed directly through the
Arduino IDE. Only minor changes were required for this compatibility.
See the Wiki to learn how to do it.

- New status reporting mask to turn on and off what Grbl sends back.
This includes machine coordinates, work coordinates, serial RX buffer
usage, and planner buffer usage. Expandable to more information on user
request, but that’s it for now.

- Settings have been completely renumbered to allow for future new
settings to be installed without having to constantly reshuffle and
renumber all of the settings every time.

- All settings masks have been standardized to mean bit 0 = X, bit 1 =
Y, and bit 2 = Z, to reduce confusion on how they work. The invert
masks used by the internal Grbl system were updated to accommodate this
change as well.

- New invert probe pin setting, which does what it sounds like.

- Fixed a probing cycle bug, where it would freeze intermittently, and
removed some redundant code.

- Homing may now be set to the origin wherever the limit switches are.
Traditionally machine coordinates should always be in negative space,
but when limit switches on are on the opposite side, the machine
coordinate would be set to -max_travel for the axis. Now you can always
make it [0,0,0] via a compile-time option in config.h. (Soft limits
routine was updated to account for this as well.)

 - Probe coordinate message immediately after a probing cycle may now
be turned off via a compile-time option in config.h. By default the
probing location is always reported.

- Reduced the N_ARC_CORRECTION default value to reflect the changes in
how circles are generated by an arc tolerance, rather than a fixed arc
segment setting.

- Increased the incoming line buffer limit from 70 to 80 characters.
Had some extra memory space to invest into this.

- Fixed a bug where tool number T was not being tracked and reported
correctly.

- Added a print free memory function for debugging purposes. Not used
otherwise.

- Realtime rate report should now work during feed holds, but it hasn’t
been tested yet.

- Updated the streaming scripts with MIT-license and added the simple
streaming to the main stream.py script to allow for settings to be sent.

- Some minor code refactoring to improve flash efficiency. Reduced the
flash by several hundred KB, which was re-invested in some of these new
features.
2014-07-26 15:01:34 -06:00

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#Grbl - An embedded g-code interpreter and motion-controller for the Arduino/AVR328 microcontroller
------------
Grbl is a no-compromise, high performance, low cost alternative to parallel-port-based motion control for CNC milling. It will run on a vanilla Arduino (Duemillanove/Uno) as long as it sports an Atmega 328.
The controller is written in highly optimized C utilizing every clever feature of the AVR-chips to achieve precise timing and asynchronous operation. It is able to maintain up to 30kHz of stable, jitter free control pulses.
It accepts standards-compliant G-code and has been tested with the output of several CAM tools with no problems. Arcs, circles and helical motion are fully supported, as well as, other basic functional g-code commands. Functions and variables are not currently supported, but may be included in future releases in a form of a pre-processor.
Grbl includes full acceleration management with look ahead. That means the controller will look up to 18 motions into the future and plan its velocities ahead to deliver smooth acceleration and jerk-free cornering.
* Note on licensing: The Grbl master branch is licensed under the MIT software license. Currently, the developmental edge branch will remain under GPLv3 until pushed to master, where it will be updated to the MIT-license. Please see the COPYING text for more details.
* For more information and help, check out our **[Wiki pages!](https://github.com/grbl/grbl/wiki)** If you find that the information is out-dated, please to help us keep it updated by editing it or notifying our community! Thanks!
* Lead Developers: Sonny Jeon, Ph.D. (2011-2014) and Simen Svale Skogsrud, a.k.a the O.G. (2009-2011)
------------
##Update Summary for v0.9 from v0.8
- **_BETA_ status:** Minor bugs may exist. Under final testing for master release. Please report any issues to administrators so we can push this out quickly!
- **IMPORTANT: Default serial baudrate is now 115200! (Up from 9600)**
- **_NEW_ Super Smooth Stepper Algorithm:** Complete overhaul of the handling of the stepper driver to simplify and reduce task time per ISR tick. Much smoother operation with the new Adaptive Multi-Axis Step Smoothing (AMASS) algorithm which does what its name implies (see stepper.c source for details). Users should immediately see significant improvements in how their machines move and overall performance!
- **Stability and Robustness Updates:** Grbl's overall stability has been focused on for this version. The planner and step-execution interface has been completely re-written for robustness and incorruptibility by the introduction of an intermediate step segment buffer that "checks-out" steps from the planner buffer in real-time. This means we can now fearlessly drive Grbl to it's highest limits. Combined with the new stepper algorithm and planner optimizations, this translated to **5x to 10x** overall performance increases in our testing! Also, stability and robustness tests have been reported to easily take 1.4 million (yes, **million**) line g-code programs like a champ!
- **(x4)+ Faster Planner:** Planning computations improved four-fold or more by optimizing end-to-end operations, which included streamlining the computations and introducing a planner pointer to locate un-improvable portions of the buffer and not waste cycles recomputing them.
- **Compile-able via Arduino IDE!:** Grbl's source code may be now download and altered, and then be compiled and flashed directly through the Arduino IDE, which should work on all platforms. See the Wiki for details on how to do it.
- **G-Code Parser Overhaul:** Completely re-written from the ground-up for 100%-compliance* to the g-code standard. (* Parts of the NIST standard are a bit out-dated and arbitrary, so we altered some minor things to make more sense. Differences are outlined in the source code.) We also took steps to allow us to break up the g-code parser into distinct separate tasks, which is key for some future development ideas and improvements.
- **Independent Acceleration and Velocity Settings:** Each axes may be defined with unique acceleration and velocity parameters and Grbl will automagically calculate the maximum acceleration and velocity through a path depending on the direction traveled. This is very useful for machines that have very different axes properties, like the ShapeOko's z-axis.
- **Soft Limits:** Checks if any motion command exceeds workspace limits before executing it, and alarms out, if detected. Another safety feature, but, unlike hard limits, position does not get lost, as it forces a feed hold before erroring out. NOTE: This still requires limit switches for homing so Grbl knows where the machine origin is, and the new max axis travel settings configured correctly for the machine.
- **Probing:** The G38.2 straight probe and G43.1/49 tool offset g-code commands are now supported. A simple probe switch must be connected to the Uno analog pin 5 (normally-open to ground). Grbl will report the probe position back to the user when the probing cycle detects a pin state change.
- **Tool Length Offsets:** Probing doesn't make sense without tool length offsets(TLO), so we added it! The G43.1 dynamic TLO (described by linuxcnc.org) and G49 TLO cancel commands are now supported. G43.1 dynamic TLO works like the normal G43 TLO(NOT SUPPORTED) but requires an additional axis word with the offset value attached. We did this so Grbl does not have to track and maintain a tool offset database in its memory. Perhaps in the future, we will support a tool database, but not for this version.
- **Improved Arc Performance:** The larger the arc radius, the faster Grbl will trace it! We are now defining arcs in terms of arc chordal tolerance, rather than a fixed segment length. This automatically scales the arc segment length such that maximum radial error of the segment from the true arc is never more than the chordal tolerance value of a super-accurate default of 0.002 mm.
- **CPU Pin Mapping:** In an effort for Grbl to be compatible with other AVR architectures, such as the 1280 or 2560, a new cpu_map.h pin configuration file has been created to allow Grbl to be compiled for them. This is currently user supported, so your mileage may vary. If you run across a bug, please let us know or better send us a fix! Thanks in advance!
- **New Grbl SIMULATOR! (by @jgeisler and @ashelly):** A completely independent wrapper of the Grbl main source code that may be compiled as an executable on a computer. No Arduino required. Simply simulates the responses of Grbl as if it was on an Arduino. May be used for many things: checking out how Grbl works, pre-process moves for GUI graphics, debugging of new features, etc. Much left to do, but potentially very powerful, as the dummy AVR variables can be written to output anything you need.
- **Configurable Real-time Status Reporting:** Users can now customize the type of real-time data Grbl reports back when they issue a '?' status report. This includes data such as: machine position, work position, planner buffer usage, serial RX buffer usage.
- **Updated Homing Routine:** Sets workspace volume in all negative space regardless of limit switch position. Common on pro CNCs. But, the behavior may be changed by a compile-time option though. Now tied directly into the main planner and stepper modules to reduce flash space and allow maximum speeds during seeking.
- **Optional Limit Pin Sharing:** Limit switches can be combined to share the same pins to free up precious I/O pins for other purposes. When combined, users must adjust the homing cycle mask in config.h to not home the axes on a shared pin at the same time. Don't worry; hard limits and the homing cycle still work just like they did before.
- **Optional Variable Spindle Speed Output:** Available only as a compile-time option through the config.h file. Enables PWM output for 'S' g-code commands. Enabling this feature will swap the Z-limit D11 pin and spindle enable D12 pin to access the hardware PWM on pin D12. The Z-limit pin, now on D12, should work just as it did before.
- **Additional Compile-Time Feature Options:** Line number tracking, real-time feed rate reporting.
- **SLATED FOR v1.0 DEVELOPMENT** Jogging controls and feedrate/spindle/coolant overrides. (In v0.9, the framework for feedrate overrides are in-place, only the minor details to complete it have yet to be installed.)
-
```
List of Supported G-Codes in Grbl v0.9
- Non-Modal Commands: G4, G10 L2, G10 L20, G28, G30, G28.1, G30.1, G53, G92, G92.1
- Motion Modes: G0, G1, G2, G3, G38.1, 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
- Coordinate System Modes: G54, G55, G56, G57, G58, G59
- Program Flow: M0, M1, M2, M30*
- Coolant Control: M7*, M8, M9
- Spindle Control: M3, M4, M5
```
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Grbl is an open-source project and fueled by the free-time of our intrepid administrators and altruistic users. If you'd like to donate, all proceeds will be used to help fund supporting hardware and testing equipment. Thank you!
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