Commit Graph

126 Commits

Author SHA1 Message Date
Elijah Insua
297f4d1dd6 report probe_succeeded with probe status 2014-09-22 20:32:47 -07:00
Elijah Insua
0beacbbb11 add probe_finalize to keep things DRY
this allows the PRB report to be valid when in "no errors" mode and the probe fails
2014-09-22 14:40:21 -07:00
Elijah Insua
5f1eece67d hop over probe pull-off sequence after probe miss
and while "no errors" is enabled (G38.3, G38.5)
2014-09-22 14:35:12 -07:00
Elijah Insua
3392a8b2c8 add/install probe_errors_enabled in mc_probe_cycle 2014-09-22 14:12:25 -07:00
Elijah Insua
5c07acd9fa test only for & PROBE_ACTIVE 2014-09-22 13:39:51 -07:00
Elijah Insua
5406fa939a cleanup global var and push probe mode into probe_get_state 2014-09-22 13:29:02 -07:00
Elijah Insua
0f7806938d install G38.{3,4,5} 2014-09-14 15:36:25 -07:00
Sonny Jeon
fc0c4f4332 Updated licensing 2014-08-07 05:58:04 -06:00
Sonny Jeon
d55f6b938c Fixed probe position sync error.
- Restored probe position syncing. Had removed a pull-off motion after
a probe cycle completes, but ended up de-synchronizing the g-code
parser and probing cycle positions. Putting the pull-off motion back
fixed the problem.
2014-08-04 05:52:41 -06:00
Sonny Jeon
469399fcd5 Probing cycle and view build info bug fixes.
- Probing cycle would drop into a QUEUED state, if multiple G38.2 are
sent. It would not honor the auto cycle start flags. To fix, the auto
cycle start state is saved at the beginning of the probing cycle and
restored at the end, since the feed hold it uses to stop a triggered
probe will disable the auto start flag. For now it’s a patch, rather
than a permanent fix.

- protocol_buffer_synchronize() also has a failure case. Auto cycle
start does not get executed when the system is waiting in here, so if
it’s in a QUEUED state already, it won’t resume. Patched here, but not
fully resolved.

- Fixed a problem with the “view build info” command. The EEPROM write
would do weird things and corrupt the EEPROM. Not sure exactly what
caused it, but it’s likely a compiler problem with an improperly
defined EEPROM address. It didn’t have enough room to store a full
string. To fix, the build info EEPROM range was increased and the max
number of STARTUP_BLOCKS was reduced to 2 from 3.

- Lastly, when a $I view build info is used for the first time, it
would normally show an EEPROM read error, since it wasn’t cleared or
wasn’t therein the first place. It will now not show that error. A
patch rather than a permanent fix again.
2014-08-03 21:10:27 -06:00
Sonny Jeon
5c0d311d92 Minor bug fixes.
- Bug fix for step and direction invert masks not immediately being in
effect. Now regenerates the masks when a user changes this setting.

- Bug fix for probing cycle. G-code standard mandates that there is an
error if the probe is already triggered when the cycle is commanded.
However, Grbl may have motions to pull off a previous probing cycle in
queue and can falsely lead to errors. To fix this, the triggered check
is performed within the probing cycle itself, right after the planner
buffer is synced. If there is an error, it will now alarm out as a
probe fail.
2014-08-01 08:29:35 -06:00
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
Sonny Jeon
87c5703200 Isolate atomic bit flag for execution.
- Denoted bit_true_atomic only for sys.execute bit settings. All other
bit_true type calls are for local variables only and don’t need atomic
access. Still looking into other ways of setting these flags without
requiring atomic access, but this is a patch for now.
2014-07-06 19:05:12 -06:00
Krzysztof Foltman
015d5fa191 Fixed atomic access to flags in sys.execute.
This seems to fix the bug that caused Grbl to hang during some operations,
especially jogging.
2014-06-26 23:06:26 +01:00
Sonny Jeon
9439e43975 Fixed spindle/coolant/dwell state check. 2014-05-29 15:41:53 -06:00
Sonny Jeon
532c359a11 Major g-code parser overhaul. 100%* compliant. Other related updates.
- Completely overhauled the g-code parser. It’s now 100%* compliant. (*
may have some bugs). Being compliant, here are some of the major
differences.

- SMALLER and JUST AS FAST! A number of optimizations were found that
sped things up and allowed for the more thorough error-checking to be
installed without a speed hit. Trimmed a lot of ‘fat’ in the parser and
still was able to make it significantly smaller than it was.

- No default feed rate setting! Removed completely! This doesn’t exist
in the g-code standard. So, it now errors out whenever it’s undefined
for motions that require it (G1/2/3/38.2).

- Any g-code parser error expunges the ENTIRE block. This means all
information is lost and not passed on to the running state. Before some
of the states would remain, which could have led to some problems.

- If the g-code block passes all of the error-checks, the g-code state
is updated and all motions are executed according to the order of
execution.

- Changes in spindle speed, when already running, will update the
output pin accordingly. This fixes a bug, where it wouldn’t update the
speed.

- Update g-code parser error reporting. Errors now return detailed
information of what exact went wrong. The most common errors return a
short text description. For less common errors, the parser reports
‘Invalid gcode ID:20’, where 20 is a error ID. A list of error code IDs
and their descriptions will be documented for user reference elsewhere
to save flash space.

- Other notable changes:

- Added a print integer routine for uint8 variables. This saved
significant flash space by switching from a heavier universal print
integer routine.

- Saved some flash space with our own short hypotenuse calculation

- Some arc computation flash and memory optimizations.
2014-05-25 16:05:28 -06:00
henols
3d053d800c Probing command gets stuck in hold if several g38.2 are submitted
Ex.
G0 X0 Y0 Z0
G38.2 Z-10 F100
G10 L20 P0 Z0
G0 Z2
G38.2 Z-1 F50
G10 L20 P0 Z0
G0 Z2
G0 X0 Y0
G38.2 Z-1 F100
G0 Z2
2014-03-07 19:33:57 +01:00
Sonny Jeon
76ab1b6a42 G38.2 probe feature rough draft installed. Working but needs testing.
- G38.2 straight probe now supported. Rough draft. May be tweaked more
as testing ramps up.

- G38.2 requires at least one axis word. Multiple axis words work too.
When commanded, the probe cycle will move at the last ‘F’ feed rate
specified in a straight line.

- During a probe cycle: If the probe pin goes low (normal high), Grbl
will record that immediate position and engage a feed hold. Meaning
that the CNC machine will move a little past the probe switch point, so
keep federates low to stop sooner. Once stopped, Grbl will issue a move
to go back to the recorded probe trigger point.

- During a probe cycle: If the probe switch does not engage by the time
the machine has traveled to its target coordinates, Grbl will issue an
ALARM and the user will be forced to reset Grbl. (Currently G38.3 probe
without error isn’t supported, but would be easy to implement later.)

- After a successful probe, Grbl will send a feedback message
containing the recorded probe coordinates in the machine coordinate
system. This is as the g-code standard on probe parameters specifies.

- The recorded probe parameters are retained in Grbl memory and can be
viewed with the ‘$#’ print parameters command. Upon a power-cycle, not
a soft-reset, Grbl will re-zero these values.

- Moved ‘$#’ command to require IDLE or ALARM mode, because it accesses
EEPROM to fetch the coordinate system offsets.

- Updated the Grbl version to v0.9d.

- The probe cycle is subject to change upon testing or user-feedback.
2014-02-28 22:03:26 -07:00
Sonny Jeon
4d7ca76f6c Probe cycle line numbers ifdef fixes to get it to compile.
- Updated some of the ifdefs when disabling line numbers feature.
Getting messy with this compile-time option. This will likely get
cleaned up later.

- This is just a push to get the new probing code to compile. Testing
and optimization of the code will soon follow and be pushed next.
2014-02-27 22:30:24 -07:00
Sonny Jeon
387a1b9f84 Merge pull request #362 from robgrz/dev
Minimal probing cycle working.  Supports both G38.2 for error and G38.3 ...
2014-02-27 20:51:38 -07:00
Sonny Jeon
8f8d8e2887 Added grbl planner Matlab simulator for test reference. Updated line number compile-time option.
- Added a grbl planner simulation tool that was written in Matlab and
Python. It was used to visualize the inner workings of the planner as a
program is streamed to it. The simulation assumes that the planner
buffer is empty, then filled, and kept filled. This is mainly for users
to see how the planner works.

- Updated some of the compile-time ifdefs when enabling line numbers.
The leaving the un-used line numbers in the function calls eats a
non-neglible amount of flash memory. So the new if-defs remove them.
2014-02-26 12:10:07 -07:00
Robert Grzesek
0a46dfe0b9 Minimal probing cycle working. Supports both G38.2 for error and G38.3 when no errors are desired. 2014-02-25 12:19:52 -08:00
Sonny Jeon
1fd45791a5 Minor updates to line number feature.
- Changed line number integer types from unsigned to signed int32.
G-code mandates values cannot exceed 99999. Negative values can be used
to indicate certain modes.

- Homing cycle line number changed to -1, as an indicator.

- Fixed a reporting define for the spindle states that was broken by
the last merge.
2014-02-19 07:48:09 -07:00
Sonny Jeon
9c95c1439f Merge pull request #356 from robgrz/dev
Line number reporting as compile-time option.
2014-02-19 07:32:51 -07:00
Sonny Jeon
b332d6edbb Commenting updates. Minor bug fix with exit of soft limit event. 2014-02-19 07:21:40 -07:00
Robert Grzesek
2307563d8a Merge commit 'cd71a90ce8a770e0030ed6c9bac805b89724e275' into dev
Conflicts:
	limits.c
	motion_control.c
	report.c
2014-02-18 18:23:39 -08:00
Sonny Jeon
50fbc6e297 Refactoring and lots of bug fixes. Updated homing cycle.
WARNING: There are still some bugs to be worked out. Please use caution
if you test this firmware.

- Feed holds work much better, but there are still some failure
conditions that need to be worked out. This is the being worked on
currently and a fix is planned to be pushed next.

- Homing cycle refactoring: Slight adjustment of the homing cycle to
allow for limit pins to be shared by different axes, as long as the
shared limit pins are not homed on the same cycle. Also, removed the
LOCATE_CYCLE portion of the homing cycle configuration. It was
redundant.

- Limit pin sharing: (See above). To clear up one or two limit pins for
other IO, limit pins can now be shared. For example, the Z-limit can be
shared with either X or Y limit pins, because it’s on a separate homing
cycle. Hard limit will still work exactly as before.

- Spindle pin output fixed. The pins weren’t getting initialized
correctly.

- Fixed a cycle issue where streaming was working almost like a single
block mode. This was caused by a problem with the spindle_run() and
coolant_run() commands and issuing an unintended planner buffer sync.

- Refactored the cycle_start, feed_hold, and other runtime routines
into the runtime command module, where they should be handled here
only. These were redundant.

- Moved some function calls around into more appropriate source code
modules.

- Fixed the reporting of spindle state.
2014-02-09 10:46:34 -07:00
Robert Grzesek
6fdb35a7da Initial line number reporting 2014-02-06 15:10:27 -08:00
Sonny Jeon
cc9afdc195 Lots of re-organization and cleaning-up. Some bug fixes.
- Added a new source and header file called system. These files contain
the system commands and variables, as well as all of the system headers
and standard libraries Grbl uses. Centralizing some of the code.

- Re-organized the include headers throughout the source code.

- ENABLE_M7 define was missing from config.h. Now there.

- SPINDLE_MAX_RPM and SPINDLE_MIN_RPM now defined in config.h. No
uncommenting to prevent user issues. Minimum spindle RPM now provides
the lower, near 0V, scale adjustment, i.e. some spindles can go really
slow so why use up our 256 voltage bins for them?

- Remove some persistent variables from coolant and spindle control.
They were redundant.

- Removed a VARIABLE_SPINDLE define in cpu_map.h that shouldn’t have
been there.

- Changed the DEFAULT_ARC_TOLERANCE to 0.002mm to improve arc tracing.
Before we had issues with performance, no longer.

- Fixed a bug with the hard limits and the software debounce feature
enabled. The invert limit pin setting wasn’t honored.

- Fixed a bug with the homing direction mask. Now is like it used to
be. At least for now.

- Re-organized main.c to serve as only as the reset/initialization
routine. Makes things a little bit clearer in terms of execution
procedures.

- Re-organized protocol.c as the overall master control unit for
execution procedures. Not quite there yet, but starting to make a
little more sense in how things are run.

- Removed updating of old settings records. So many new settings have
been added that it’s not worth adding the code to migrate old user
settings.

- Tweaked spindle_control.c a bit and made it more clear and consistent
with other parts of Grbl.

- Tweaked the stepper disable bit code in stepper.c. Requires less
flash memory.
2014-01-10 20:22:10 -07:00
Sonny Jeon
f10bad43b2 Minor bug fixes: Homing travel calculations. Cycle resuming after spindle and dwell commands.
- Homing travel calculations fixed. It was computing the min travel
rather than max.

- Auto-start disable and pausing after spindle or dwell commands.
Related to plan_synchronize() function call. Now fixed, but still need
to work on the system state.

- Pushed a fix to make this branch more Arduino IDE compatible. Removed
extern call in nuts_bolts.c

- Updated the stepper configuration option of enabling or disabling the
new Adaptive Multi-Axis Step Smoothing Algorithm. Now works either way.

- Updated some copyright info.
2013-12-30 22:02:05 -07:00
Sonny Jeon
47cd40c8dc Incomplete push but working. Lots more stuff. More to come.
- NEW! An active multi-axis step smoothing algorithm that automatically
adjusts dependent on step frequency. This solves the long standing
issue to aliasing when moving with multiple axes. Similar in scheme to
Smoothieware, but more advanced in ensuring a more consistent CPU
overhead throughout all frequencies while maintaining step exactness.

- Switched from Timer2 to Timer0 for the Step Port Reset Interrupt.
Mainly to free up hardware PWM pins.

- Seperated the direction and step pin assignments, so we can now move
them to seperate ports. This means that we can more easily support 4+
axes in the future.

- Added a setting for inverting the limit pins, as so many users have
request. Better late than never.

- Bug fix related to EEPROM calls when in cycle. The EEPROM would kill
the stepper motion. Now protocol mandates that the system be either in
IDLE or ALARM to access or change any settings.

- Bug fix related to resuming the cycle after a spindle or dwell
command if auto start has been disabled. This fix is somewhat temporary
or more of a patch. Doesn’t work with a straight call-response
streaming protocol, but works fine with serial buffer pre-filling
streaming that most clients use.

- Renamed the pin_map.h to cpu_map.h to more accurately describe what
the file is.

- Pushed an auto start bug fix upon re-initialization.

- Much more polishing to do!
2013-12-30 18:44:46 -07:00
Sonny Jeon
903b462b2e Merge branch 'dev' of https://github.com/grbl/grbl into dev
Conflicts:
	limits.c
2013-12-29 20:34:51 -07:00
Sonny Jeon
b8f0a2399e Merge fixes. 2013-10-29 19:28:44 -06:00
Sonny Jeon
4f9bcde40e Merge branch 'dev_2' into dev
Conflicts:
README.md
gcode.c
motion_control.c
planner.c
planner.h
protocol.c
report.c
settings.c
settings.h
stepper.c
stepper.h
2013-10-29 19:10:39 -06:00
Sonny Jeon
b06643a2e0 Bug fix to-do note on soft limit checks. Not yet completed. 2013-03-01 10:50:36 -07:00
Sonny Jeon
74b2af3c2f Minor changes and added notes to soft limits routines.
- Changed up mc_line to accept an array rather than individual x,y,z
coordinates. Makes some of the position data handling more effective,
especially for a 4th-axis later on.

- Changed up some soft limits variable names.
2013-03-01 09:55:10 -07:00
bungao
b75e95c880 integrating soft limits 2013-02-26 13:55:12 +11:00
Sonny Jeon
97d18f0ffe Merge bug fixes from recent v0.8c push. Added readme for Grbl Sim. 2013-01-18 17:02:44 -07:00
Sonny Jeon
5e7c25d480 Updated README. Max step rate back at 30kHz. Acceleration minor bug fix.
- Returned the max step rate to 30kHz. The new arc algorithm works uses
so much less CPU overhead, because the segments are longer, that the
planner has no problem computing through them.

- Fixed an issue with the acceleration independence scaling. Should now
work with accelerations above 400mm/sec^2 or so.

- Updated README
2012-12-21 08:51:36 -07:00
Sonny Jeon
3dfffa622d Arc mm_per_segment removed, now in terms of tolerance. Stepper ramp counter variable type corrected.
- 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.
2012-12-19 17:30:09 -07:00
Sonny Jeon
a1397f61c4 Max velocity axes independence installed. Fixed intermittent slow trailing steps. Timer0 disable fix.
- Maximum velocity for each axis is now configurable in settings. All
rapids/seek move at these maximums. All feed rates(including rapids)
may be limited and scaled down so that no axis does not exceed their
limits.

- Moved around auto-cycle start. May change later, but mainly to ensure
the planner buffer is completely full before cycle starting a streaming
program. Otherwise it should auto-start when there is a break in the
serial stream.

- Reverted old block->max_entry_speed_sqr calculations. Feedrate
overrides not close to ready at all.

- Fixed intermittent slow trailing steps for some triangle velocity
profile moves. The acceleration tick counter updating was corrected to
be exact for that particular transition. Should be ok for normal
trapezoidal profiles.

- Fixed the Timer0 disable after a step pulse falling edge. Thanks
@blinkenlight!
2012-12-16 16:23:24 -07:00
Sonny Jeon
bba633101a G28/G30 post move bug fix. Altered file permissions. 2012-11-25 22:02:33 -07:00
Sonny Jeon
d85238cc9b Homing search sequence now compile-time option. New defaults.h file. Tidying up.
- 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.
2012-11-18 19:52:16 -07:00
Sonny Jeon
5dd6d90122 Added Grbl state in status report. Removed switch support.
- Added Grbl state (Idle, Running, Queued, Hold, etc) to the real-time
status reporting feature as feedback to the user of what Grbl is doing.
Updated the help message to reflect this change.

- Removed switches (dry run, block delete, single block mode). To keep
Grbl simple and not muddled up from things that can easily be taken
care of by an external interface, these were removed.

- Check g-code mode was retained, but the command was moved to '$C'
from '$S0'.
2012-11-15 21:53:11 -07:00
Sonny Jeon
559feb97e2 Re-factored system states and alarm management. Serial baud support greater than 57600.
- Refactored system states to be more clear and concise. Alarm locks
processes when position is unknown to indicate to user something has
gone wrong.

- Changed mc_alarm to mc_reset, which now manages the system reset
function. Centralizes it.

- Renamed '$X' kill homing lock to kill alarm lock.

- Created an alarm error reporting method to clear up what is an alarm:
message vs a status error: message. For GUIs mainly. Alarm codes are
negative. Status codes are positive.

- Serial baud support upto 115200. Previous baudrate calc was unstable
for 57600 and above.

- Alarm state locks out all g-code blocks, including startup scripts,
but allows user to access settings and internal commands. For example,
to disable hard limits, if they are problematic.

- Hard limits do not respond in an alarm state.

- Fixed a problem with the hard limit interrupt during the homing
cycle. The interrupt register is still active during the homing cycle
and still signal the interrupt to trigger when re-enabled. Instead,
just disabled the register.

- Homing rate adjusted. All axes move at homing seek rate, regardless
of how many axes move at the same time. This is unlike how the stepper
module does it as a point to point rate.

- New config.h settings to disable the homing rate adjustment and the
force homing upon powerup.

- Reduced the number of startup lines back down to 2 from 3. This
discourages users from placing motion block in there, which can be very
dangerous.

- Startup blocks now run only after an alarm-free reset or after a
homing cycle. Does not run when $X kill is called. For satefy reasons
2012-11-14 17:36:29 -07:00
Sonny Jeon
e6ad15b548 Tweaks. Seek rate updates when set. CCW arc full circle fix.
- Fixed a minor issue where the seek rates would not immediately be
used and only would after a reset. Should update live now.

- A full circle IJ offset CCW arc would not do anything. Fixed bug via
a simple if-then statement.

- Radius mode tweaks to check for negative value in sqrt() rather than
isnan() it. Error report updated to indicate what actually happened.
2012-11-10 12:49:33 -07:00
Sonny Jeon
978de77c2f Added note that D13 can't be used as input, pulled-high. 2012-11-09 18:33:38 -07:00
Sonny Jeon
5844172af1 Fixed homing cycle hanging after locating switches. 2012-11-09 16:25:42 -07:00
Sonny Jeon
f41dd69273 Tweaks and bug fixes. Increase to 3 startup blocks. Remove purge/added unlock command
- Increased the number of startup blocks to 3 for no good reason other
than it doesn't increase the flash size.

- Removed the purge buffer command and replaced with an disable homing
lock command.

- Homing now blocks all g-code commands (not system commands) until the
homing cycle has been performed or the disable homing lock is sent.
Homing is required upon startup or if Grbl loses it position. This is
for safety reasons.

- Cleaned up some of the Grbl states and re-organized it to be little
more cohesive.

- Cleaned up the feedback and status messages to not use so much flash
space, as it's a premium now.

 - Check g-code and dry run switches how are mutually exclusive and
can't be enabled when the other is. And automatically resets Grbl when
disabled.

- Some bug fixes and other minor tweaks.
2012-11-05 21:40:52 -07:00
Sonny Jeon
8c0106c247 Tweaks and minor bug fixes. Added purge buffer command.
- Added a purge buffer (and lock) command. This is an advanced option
to clear any queued blocks in the buffer in the event of system
position being lost or homed. These queued blocks will likely not move
correctly if not purged. In typical use, the purging command releases
the homing axes lock in case a user need to move the axes off their
hard limit switches, but position is not guaranteed. Homing is advised
immediately after.

- Created a system-wide sync current position function. Cleans up some
of the repetitive tasks in various places in the code that do the same
thing.

- Removed the clear all switches command '$S'. Not really needed and
helped clean up a sync call.

- Other minor tweaks. Readme updated slightly..
2012-11-04 08:44:54 -07:00