- Updated config comments and stepper code comments for the new changes.
- Changed stepper algorithm variable names to be more understandable in
what they actually do.
- Added a stepper lock note in default.h per user request.
- Started some code layout in handling feed holds and refactoring the
homing routine to use the main stepper algorithm instead of a seperate
version.
- Cleaned up the new stepper algorithm code with more commenting and
better logic flow.
- The new segment buffer now predicts the number of steps each segment
should have to execute over about 8 milliseconds each (based on the
ACCELERATION_TICKS_PER_SECOND setting). So, for when the whole segment
buffer is full, the stepper algorithm has roughly 40 milliseconds of
steps queued before it needs to refilled by the main program.
- Readjusted the max supported step rate back to 30kHz from the lower
development 20kHz. Everything still works amazing great and the test
CNC machine still runs twice as fast with the new stepper algorithm and
planner.
- Upped the standard serial baudrate to 115200 baud, as it is clear
that the bottleneck is the serial interface. Will now support this, as
well as the old 9600 baud, in new firmware builds.
- WARNING: Completely untested. Will later when there is time. Settings
WILL be overwritten, as there are new settings.
- Soft limits installed. Homing must be enabled for soft limits to work
correctly. Errors out much like a hard limit, locking out everything
and bringing up the alarm mode. Only difference is it forces a feed
hold before doing so. Position is not lost.
- IMPORTANT: Homing had to be updated so that soft limits work better
with less CPU overhead. When homing completes, all axes are assumed to
exist in negative space. If your limit switch is other side, the homing
cycle with set this axis location to the max travel value, rather than
zero.
- Update mc_line() to accept an array, rather than individual variables.
- Added an mc_auto_cycle_start() function handle this feature.
Organization only.
-
- Arc mm_per_segment parameter was removed and replaced with an
arc_tolerance parameter, which scales all arc segments automatically to
radius, such that the line segment error doesn't exceed the tolerance.
Significantly improves arc performance through larger radius arc,
because the segments are much longer and the planner buffer has more to
work with.
- Moved n_arc correction from the settings to config.h. Mathematically
this doesn't need to be a setting anymore, as the default config value
will work for all known CNC applications. The error does not accumulate
as much anymore, since the small angle approximation used by the arc
generation has been updated to a third-order approximation and how the
line segment length scale with radius and tolerance now. Left in
config.h for extraneous circumstances.
- Corrected the st.ramp_count variable (acceleration tick counter) to a
8-bit vs. 32-bit variable. Should make the stepper algorithm just a
touch faster overall.
- Planner execute speed has been more than halved from 4ms to 1.9ms
when computing a plan for a single line segment during arc generation.
This means that Grbl can now run through an arc (or complex curve)
twice as fast as before without starving the buffer. For 0.1mm arc
segments, this means about the theoretical feed rate limit is about
3000mm/min for arcs now.
- Increased the Ranade timer frequency to 30kHz, as there doesn't seem
to be any problems with increasing the frequency. This means that the
maximum step frequency is now back at 30kHz.
- Added Zen Toolworks 7x7 defaults.
- Brand-new stepper algorithm. Based on the Pramod Ranade inverse time
algorithm, but modified to ensure step events are exact. Currently
limited to about 15kHz step rates, much more to be done to enable 30kHz
again.
- Removed Timer1. Stepper algorithm now uses Timer0 and Timer2.
- Much improved step generation during accelerations. Smoother. Allows
much higher accelerations (and speeds) than before on the same machine.
- Cleaner algorithm that is more easily portable to other CPU types.
- Streamlined planner calculations. Removed accelerate_until and
final_rate variables from block buffer since the new stepper algorithm
is that much more accurate.
- Improved planner efficiency by about 15-20% during worst case
scenarios (arcs).
- New config.h options to tune new stepper algorithm.
- Updated interface protocol to play nicer with interface programs. All
Grbl responses beginning with '$' signifies a setting. Bracketed '[]'
responses are feedback messages containing either state, parameter, or
general messages. Chevron '<>' response are from the real-time status
messages, i.e. position.
- M2 Program end command was causing a system alarm. Fixed. Thanks
@blinkenlight !
- The homing sequence is now a compile-time option, where a user can
choose which axes(s) move in sequence during the search phase. Up to 3
sequences. Works with the locating phase and the pull-off maneuver.
- New defaults.h file to store user generated default settings for
different machines. Mainly to be used as a central repo, but each set
may be select to be compiled in as a config.h define.
