grbl-LPC-CoreXY/doc/log/commit_log_v0.9i.txt

----------------
Date: 2015-08-29
Author: Sonny Jeon
Subject: Optional line number reporting bug fix.

- Fixed a bug where it would not compile when USE_LINE_NUMBERS was
enabled.


----------------
Date: 2015-08-27
Author: Sonny Jeon
Subject: Update README


----------------
Date: 2015-08-27
Author: Sonny Jeon
Subject: v1.0 Beta Release.

- Tons of new stuff in this release, which is fairly stable and well
tested. However, much more is coming soon!

- Real-time parking motion with safety door. When this compile option
is enabled, an opened safety door will cause Grbl to automatically feed
hold, retract, de-energize the spindle/coolant, and parks near Z max.
After the door is closed and resume is commanded, this reverses and the
program continues as if nothing happened. This is also highly
configurable. See config.h for details.

- New spindle max and min rpm ‘$’ settings! This has been requested
often. Grbl will output 5V when commanded to turn on the spindle at its
max rpm, and 0.02V with min rpm. The voltage and the rpm range are
linear to each other. This should help users tweak their settings to
get close to true rpm’s.

- If the new max rpm ‘$’ setting is set = 0 or less than min rpm, the
spindle speed PWM pin will act like a regular on/off spindle enable
pin. On pin D11.

- BEWARE: Your old EEPROM settings will be wiped! The new spindle rpm
settings require a new settings version, so Grbl will automatically
wipe and restore the EEPROM with the new defaults.

- Control pin can now be inverted individually with a
CONTROL_INVERT_MASK in the cpu_map header file. Not typical for users
to need this, but handy to have.

- Fixed bug when Grbl receive too many characters in a line and
overflows. Previously it would respond with an error per overflow
character and another acknowledge upon an EOL character. This broke the
streaming protocol. Now fixed to only respond with an error after an
EOL character.

- Fixed a bug with the safety door during an ALARM mode. You now can’t
home or unlock the axes until the safety door has been closed. This is
for safety reasons (obviously.)

- Tweaked some the Mega2560 cpu_map settings . Increased segment buffer
size and fixed the spindle PWM settings to output at a higher PWM
frequency.

- Generalized the delay function used by G4 delay for use by parking
motion. Allows non-blocking status reports and real-time control during
re-energizing of the spindle and coolant.

- Added spindle rpm max and min defaults to default.h files.

- Added a new print float for rpm values.


----------------
Date: 2015-08-14
Author: Sonny Jeon
Subject: Individual control pin invert compile-option.

- Control pins may be individually inverted through a
CONTROL_INVERT_MASK macro. This mask is define in the cpu_map.h file.


----------------
Date: 2015-07-17
Author: Sonny Jeon
Subject: Version bump to v0.9j

- Version bump requested by OEMs to easily determine whether the
firmware supports the new EEPROM reset feature. Other than that, no
significant changes.


----------------
Date: 2015-06-25
Author: Sonny Jeon
Subject: Restore parameters minor bug fix.

- `$RST=#` was not wiping the G30 positions from EEPROM. Minor but now
fixed.


----------------
Date: 2015-06-20
Author: Sonny Jeon
Subject: New EEPROM restore functions.

- Tweaked the previous EEPROM restore implementation and added new
functionality.

- `$RST=$` restores the `$$` grbl settings back to firmware defaults,
which are set when compiled.

- `$RST=#` restores the `$#` parameters in EEPROM. At times it’s useful
to clear these and start over, rather than manually writing each entry.

-`$RST=*` wipe all of the data in EEPROM that Grbl uses and restores
them to defaults. This includes `$$` settings, `$#` parameters, `$N`
startup lines, and `$i` build info string.

NOTE: This doesn’t write zeros throughout the EEPROM. It only writes
where Grbl looks for data. For a complete wipe, please use the Arduino
IDE’s EEPROM clear example.

- Refactored the restore and wipe functions in settings.c to
accommodate the new commands.


----------------
Date: 2015-06-18
Author: Sonny Jeon
Subject: Updated README


----------------
Date: 2015-06-18
Author: Sonny Jeon
Subject: Added restore settings defaults command.

- New restore setting defaults command. Only wipes ‘$$’ setting in
EEPROM and reloads them based on the defaults used when Grbl was
compiled. Used with a `$RST` command

NOTE: `$RST` is intentionally not listed in the Grbl ‘$’ help message.


----------------
Date: 2015-05-29
Author: Sonny Jeon
Subject: Added G61 exact path support.

- G61 exact path is the Grbl default path control mode, so it’s now
added as a supported g-code.


----------------
Date: 2015-05-27
Author: Sonny Jeon
Subject: Another git case-sensitive folder fix.

- I’m now officially annoyed.


----------------
Date: 2015-05-27
Author: Sonny Jeon
Subject: Added X-Carve defaults.

- Added X-Carve 500mm and 1000mm default files.

- Tweaked all default files. Removed obsolete AUTO_START and updated
some JUNCTION_DEVIATION defaults after testing showed these needed to
be reduced slightly.


----------------
Date: 2015-05-27
Author: Sonny Jeon
Subject: Merge pull request #710 from buserror/fix-directory-case-sensitivity

Rename Grbl to grbl

----------------
Date: 2015-05-27
Author: Michel Pollet
Subject: Rename Grbl to grbl

Otherwise compilation fails on linux, or other case sensitive systems

Signed-off-by: Michel Pollet <buserror@gmail.com>


----------------
Date: 2015-05-26
Author: Sonny Jeon
Subject: Updated README


----------------
Date: 2015-05-26
Author: Sonny Jeon
Subject: Merge pull request #706 from grbl/edge

Merge edge branch.

----------------
Date: 2015-05-23
Author: Sonny Jeon
Subject: CoreXY planner bug fix.

- CoreXY motions were moving to the negative value of the intended
target. Now fixed.


----------------
Date: 2015-05-23
Author: Sonny Jeon
Subject: Moved cpu_map.

- Moved cpu_map files to a cpu_map directory, like the defaults file
organization.


----------------
Date: 2015-05-23
Author: Sonny Jeon
Subject: Homing and limit updates. Minor bug fixes.

- Updated new homing cycle to error out when a pull-off motion detects
the limit is still active.

- Created a limits_get_state() function to centralize it. It reports
state as a bit-wise booleans according to axis numbering.

- Updated the print uint8 functions. Generalized it to allow both base2
and base10 printouts, while allowing base2 prints with N_AXIS digits
for limit state status reports. Doing this saved about 100bytes of
flash as well.

- Applied CoreXY status reporting bug fix by @phd0. Thanks!


----------------
Date: 2015-05-22
Author: Sonny Jeon
Subject: Merge pull request #702 from ashelly/default-split

Moving defaults to individual files in subdirectory

----------------
Date: 2015-05-22
Author: ashelly
Subject: Moving defaults to individual files in subdirectory


----------------
Date: 2015-05-22
Author: Sonny Jeon
Subject: Merge pull request #700 from ashelly/header-split

Header split

----------------
Date: 2015-05-22
Author: ashelly
Subject: Fixing up comment blocks in headers


----------------
Date: 2015-05-22
Author: ashelly
Subject: Splitting Cpu map into separate files.

Makes comparison, addition of new ones easier


----------------
Date: 2015-05-17
Author: Sonny Jeon
Subject: Critical M0/2/30 fix. Homing updates.

- Critical fix for M0 program pause. Due to its recent change, it would
cause Grbl to suspend but wouldn’t notify the user of why Grbl was not
doing anything. The state would show IDLE and a cycle start would
resume it. Grbl now enters a HOLD state to better indicate the state
change.

- Critical fix for M2 and M30 program end. As with M0, the state
previously would show IDLE while suspended. Grbl now does not suspend
upon program end and leaves job control to the GUI. Grbl simply reports
a `[Pgm End]` as a feedback message and resets certain g-code modes.

- M2/30 g-code reseting fix. Previously Grbl would soft-reset after an
M2/30, but this was not complaint to the (linuxcnc) g-code standard. It
simply resets [G1,G17,G90,G94,G40,G54,M5,M9,M48] and keeps all other
modes the same.

- M0/M2/M30 check-mode fix. It now does not suspend the machine during
check-mode.

- Minor bug fix related to commands similar to G90.1, but not G90.1,
not reporting an unsupported command.

- Homing cycle refactoring. To help reduce the chance of users
misunderstanding their limit switch wiring, Grbl only moves a short
distance for the locate cycles only. In addition, the homing cycle
pulls-off the limit switch by the pull-off distance to re-engage and
locate home. This should improve its accuracy.

- HOMING_FORCE_ORIGIN now sets the origin to the pull-off location,
rather than where the limit switch was triggered.

- Updated default junction deviation to 0.01mm. Recent tests showed
that this improves Grbl’s cornering behavior a bit.

- Added the ShapeOko3 defaults.

- Added new feedback message `[Pgm End]` for M2/30 notification.

- Limit pin reporting is now a $10 status report option. Requested by
OEMs to help simplify support troubleshooting.


----------------
Date: 2015-03-29
Author: Sonny Jeon
Subject: Fix for limit pin reporting compile-option

- The limit pin reporting wasn’t working correctly due to calling the
wrong similarly-named function. Verified to be working now.


----------------
Date: 2015-03-29
Author: Sonny Jeon
Subject: Commit history, logo license, full-arc fix.

- Commit history added to repo, as an easier way for people to see view
the changes over time.

- Grbl logo copyright license added. All rights reserved with regards
to the Grbl logo.

- G2/3 full circles would sometime not execute. The problem was due to
numerical round-off of a trig calculation. Added a machine epsilon
define to help detect and correct for this problem. Tested and should
not effect general operation of arcs.


----------------
Date: 2015-03-27
Author: Sungeun Jeon
Subject: Compile-option for inverting spindle enable.

- Installed a compile-option for inverting the spindle enable pin for
certain electronics boards users have reported needing this.


----------------
Date: 2015-03-27
Author: Sungeun Jeon
Subject: New compile options and inverse time bug fix.

- Apparently inverse time motion were not working for quite some time.
Goes to show how many people actually use it. The calculation was bad
and is now fixed in this update. It should now work correctly.

- `;` comment type is now supported. This is standard on LinuxCNC and
common on 3d printers. It was previously not supported due to not
existing in the NIST standard, which is out-dated.

- New compile-option to ECHO the line received. This should help users
experiencing very weird problems and help diagnose if there is
something amiss in the communication to Grbl.

- New compile-option to use the spindle direction pin D13 as a spindle
enable pin with PWM spindle speed on D11. This feature has been
requested often from the laser cutter community. Since spindle
direction isn’t really of much use, it seemed like good good trade.
Note that M4 spindle enable counter-clock-wise support is removed for
obvious reasons, while M3 and M5 still work.


----------------
Date: 2015-03-27
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2015-03-26
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2015-03-16
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2015-03-15
Author: Sungeun Jeon
Subject: Updated README


----------------
Date: 2015-03-15
Author: Sonny Jeon
Subject: Create README.md

----------------
Date: 2015-03-15
Author: Sungeun Jeon
Subject: Merge branch 'edge'


----------------
Date: 2015-03-15
Author: Sungeun Jeon
Subject: Updated README.

- Also altered the G38.X reporting to save some bytes.


----------------
Date: 2015-03-14
Author: Sungeun Jeon
Subject: Cleaned-up limit pin reporting and comments.

- Cleaned up the limit pin state reporting option to display only the
state per axis, rather than the whole port. It’s organized by an XYZ
order, 0(low)-1(high), and generally looks like `Lim:001`.

- Separated the control pin state reporting from limit state reporting
as a new compile option. This stayed the same in terms of showing the
entire port in binary, since it’s not anticipated that this will be
used much, if at all.

- Updated some of the gcode source comments regarding supported g-codes.


----------------
Date: 2015-03-07
Author: Sonny Jeon
Subject: Another homing cycle fix.

- The homing cycle should be working again. Reverted it back to how it
was about a month ago before I started to fiddle with it. Turns out
that my past self knew what he was doing.


----------------
Date: 2015-03-04
Author: Sonny Jeon
Subject: Arduino IDE compatibility and minor homing fixes

- Added an include in the right spot, if a user tries to compile and
upload Grbl through the Arduino IDE with the old way.

- Fixed a minor bug with homing max travel calculations. It was causing
simultaneous axes homing to move slow than it did before.


----------------
Date: 2015-02-25
Author: Sonny Jeon
Subject: G91.1 support. Fixed a config.h option.

- G91.1 support added. This g-code sets the arc IJK distance mode to
incremental, which is the default already. This simply  helps reduce
parsing errors with certain CAM programs that output this command.

- Max step rate checks weren’t being compiled in if the option was
enabled. Fixed now.

- Alarm codes were not displaying correctly when GUI reporting mode was
enabled. Due to unsigned int problem. Changed codes to positive values
since they aren’t shared with other codes.


----------------
Date: 2015-02-23
Author: Sonny Jeon
Subject: Fixed config.h to Grbl release defaults.

- REPORT_GUI_MODE was accidentally enabled, when it shouldn’t have.


----------------
Date: 2015-02-23
Author: Sonny Jeon
Subject: New configuration options.

- New configuration option at compile-time:
 - Force alarm upon power-up or hard reset. When homing is enabled,
this is already the default behavior. This simply forces this all of
the time.
 - GUI reporting mode. Removes most human-readable strings that GUIs
don’t need. This saves nearly 2KB in flash space that can be used for
other features.
 - Hard limit force state check: In the hard limit pin change ISR, Grbl
by default sets the hard limit alarm upon any pin change to guarantee
the alarm is set. If this option is set, it’ll check the state within
the ISR, but can’t guarantee the pin will be read correctly if the
switch is bouncing. This option makes hard limit behavior a little less
annoying if you have a good buffered switch circuit that removes
bouncing and electronic noise.

- Software debounce bug fix. It was reading the pin incorrectly for the
setting.

- Re-factored some of the ‘$’ settings code.


----------------
Date: 2015-02-15
Author: Sonny Jeon
Subject: Improved homing limit search handling.

- Instead of a single overall max travel for a search distance for the
homing limit switches. The homing cycle now applies the max travel of
each axis to the search target. Generally makes more sense this way and
saved more than a 100bytes of flash too.


----------------
Date: 2015-02-15
Author: Sonny Jeon
Subject: Homing alarm upon no switch. Licensing update.

- Homing cycle failure reports alarm feedback when the homing cycle is
exited via a reset, interrupted by a safety door switch, or does not
find the limit switch.

- Homing cycle bug fix when not finding the limit switch. It would just
idle before, but now will exit with an alarm.

- Licensing update. Corrected licensing according to lawyer
recommendations. Removed references to other Grbl versions.


----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Merge pull request #593 from poelstra/fix_makefile_deps

Fix generating header dependencies, merge with 'normal' compile, force r...

----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Updated README with new logo sized for github.


----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Doc re-org. New Grbl Logos!


----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Merge pull request #591 from EliteEng/edge

Safety Door Update for Mega2560

----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Merge pull request #592 from poelstra/fix_softlimit

Fix EXEC_ALARM_* flags: soft limit would lead to hard limit error.

----------------
Date: 2015-02-13
Author: Sonny Jeon
Subject: Merge pull request #594 from poelstra/fix_sim_build

Fix function signature of print_uint32_base10(), necessary for compiling simulator.

----------------
Date: 2015-02-13
Author: Martin Poelstra
Subject: Fix function signature of print_uint32_base10(), necessary for compiling simulator.


----------------
Date: 2015-02-13
Author: Martin Poelstra
Subject: Fix generating header dependencies, merge with 'normal' compile, force recompile when files are removed.


----------------
Date: 2015-02-13
Author: Martin Poelstra
Subject: Fix EXEC_ALARM_* flags: soft limit would lead to hard limit error.


----------------
Date: 2015-02-13
Author: Rob Brown
Subject: Safety Door Update for Mega2560


----------------
Date: 2015-02-11
Author: Sonny Jeon
Subject: Overhauled state machine. New safety door feature.

- Overhauled the state machine and cleaned up its overall operation.
This involved creating a new ‘suspend’ state for what all external
commands, except real-time commands, are ignored. All hold type states
enter this suspend state.

- Removed ‘auto cycle start’ setting from Grbl. This was not used by
users in its intended way and is somewhat redundant, as GUI manage the
cycle start by streaming. It also muddled up how Grbl should interpret
how and when to execute a g-code block. Removing it made everything
much much simpler.

- Fixed a program pause bug when used with other buffer_sync commands.

- New safety door feature for OEMs. Immediately forces a feed hold and
then de-energizes the machine. Resuming is blocked until the door is
closed. When it is, it re-energizes the system and then resumes on the
normal toolpath.

- Safety door input pin is optional and uses the feed hold pin on A1.
Enabled by config.h define.

- Spindle and coolant re-energizing upon a safety door resume has a
programmable delay time to allow for complete spin up to rpm and
turning on the coolant before resuming motion.

- Safety door-style feed holds can be used instead of regular feed hold
(doesn’t de-energize the machine) with a ‘@‘ character. If the safety
door input pin is not enabled, the system can be resumed at any time.


----------------
Date: 2015-02-10
Author: Sonny Jeon
Subject: Git fix for empty directory. Makefile updated.

- ‘build’ directory was not being synced by git because it was empty.
Added a .gitignore file in the ‘build’ directory to force git to sync
it but keep it empty.

- Updated the Makefile to not erase the .gitignore.


----------------
Date: 2015-02-10
Author: Sonny Jeon
Subject: File re-organization. New Makefile.

- Re-organized source code files into a ‘grbl’ directory to lessen one
step in compiling Grbl through the Arduino IDE.

- Added an ‘examples’ directory with an upload .INO sketch to further
simplify compiling and uploading Grbl via the Arduino IDE.

- Updated the Makefile with regard to the source code no longer being
in the root directory. All files generated by compiling is placed in a
separate ‘build’ directory to keep things tidy. The makefile should
operate in the same way as it did before.


----------------
Date: 2015-02-10
Author: Sonny Jeon
Subject: Bug fix for certain motions. Re-org of includes.

- Critical bug fix for diagonal motions that continue on the same
direction or return in the exact opposite direction. This issue could
cause Grbl to crash intermittently due to a numerical round-off error.
Grbl versions prior to v0.9g shouldn’t have this issue.

- Reorganized all of the includes used by Grbl. Centralized it into a
single “grbl.h” include. This will help simplify the compiling and
uploading process through the Arduino IDE.

- Added an example .INO file for users to simply open and run when
compiling and uploading through the IDE. More to come later.


----------------
Date: 2015-02-06
Author: Sonny Jeon
Subject: Limit/control pin state reporting option

- As a setup feature, users can compile-in input pin status reporting.
Doesn’t do anything special, just prints the binary for the port. 0’s
and 1’s indicate low and high signals on the pins. It’s a bit cryptic
right now, but it’s just a start.

- Added a max step rate check when writing step/mm and max rate
settings. Should help avoid people misdiagnosing problems associated
with going over the 30kHz step rate limit. Right now not enabled. Takes
up over 100k of flash. Need that room for other things right now.


----------------
Date: 2015-02-04
Author: Sonny Jeon
Subject: Rare planner bug fix and added simulator defaults.

- Planner bug when moving along a diagonal back and forth on the same
path. Rare for the fact that most CAM programs don’t program this type
of motion, neither does jogging. Fixed in this update.

- Added grbl_sim defaults for testing purposes.


----------------
Date: 2015-01-17
Author: Sonny Jeon
Subject: Fully configurable pins for NO or NC switches.

- All pins, which include limits, control command, and probe pins, can
now all be configured to trigger as active-low or active-high and
whether the pin has its internal pull-up resistor enabled. This should
allow for just about all types of NO and NC switch configurations.

- The probe pin invert setting hasn’t been added to the Grbl settings,
like the others, and will have to wait until v1.0. But for now, it’s
available as a compile-time option in config.h.

- Fixed a variable spindle bug.


----------------
Date: 2015-01-14
Author: Sonny Jeon
Subject: Lot of refactoring for the future. CoreXY support.

- Rudimentary CoreXY kinematics support. Didn’t test, but homing and
feed holds should work. See config.h. Please report successes and
issues as we find bugs.

- G40 (disable cutter comp) is now “supported”. Meaning that Grbl will
no longer issue an error when typically sent in g-code program header.

- Refactored coolant and spindle state setting into separate functions
for future features.

- Configuration option for fixing homing behavior when there are two
limit switches on the same axis sharing an input pin.

- Created a new “grbl.h” that will eventually be used as the main
include file for Grbl. Also will help simply uploading through the
Arduino IDE

- Separated out the alarms execution flags from the realtime (used be
called runtime) execution flag variable. Now reports exactly what
caused the alarm. Expandable for new alarms later on.

- Refactored the homing cycle to support CoreXY.

- Applied @EliteEng updates to Mega2560 support. Some pins were
reconfigured.

- Created a central step to position and vice versa function. Needed
for non-traditional cartesian machines. Should make it easier later.

- Removed the new CPU map for the Uno. No longer going to used. There
will be only one configuration to keep things uniform.


----------------
Date: 2014-11-05
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2014-10-29
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2014-10-28
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2014-10-28
Author: Sonny Jeon
Subject: Update README.md

----------------
Date: 2014-10-01
Author: Sonny Jeon
Subject: Updated variable spindle and new probing. Minor bug fixes.

- Minor bug fix for variable spindle PWM output. Values smaller than
the minimum RPM for the spindle would overflow the PWM value. Thanks
Rob!

- Created an optional minimum spindle PWM low-mark value as a
compile-time option. This is for special circumstances when the PWM has
to be at a certain level to be read by the spindle controller.

- Refactored the new probing commands (G38.3, G38.4, G38.5) code to
work better with the rest of Grbl’s systems.

- Refactored mc_probe() and mc_arc() to accept the mode of the command,
i.e. clockwise vs counter, toward vs away, etc. This is to make these
functions independent of gcode state variables.

- Removed the pull off motion in the probing cycle. This is not an
official operation and was added for user simplicity, but wrongly did
so. So bye bye.

- Created a configure probe invert mask function to handle the
different probe pin setting and probing cycle modes with a single mask.

 - Minor bug fix with reporting motion modes via $G. G38.2 wasn’t
showing up. It now does, along with the other new probing commands.

- Refactored some of the new pin configurations for the future of Grbl.

-


----------------
Date: 2014-09-25
Author: Sonny Jeon
Subject: Merge pull request #491 from tmpvar/G38.2+

G38.2+

----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: report probe_succeeded with probe status


----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: add probe_finalize to keep things DRY

this allows the PRB report to be valid when in "no errors" mode and the probe fails

----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: hop over probe pull-off sequence after probe miss

and while "no errors" is enabled (G38.3, G38.5)


----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: add/install probe_errors_enabled in mc_probe_cycle


----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: bump mantissa to uint16_t to enable G38.5

----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: test only for & PROBE_ACTIVE


----------------
Date: 2014-09-22
Author: Elijah Insua
Subject: cleanup global var and push probe mode into probe_get_state


----------------
Date: 2014-09-20
Author: Sonny Jeon
Subject: Edit hard limit check at start of homing cycle


----------------
Date: 2014-09-20
Author: Sonny Jeon
Subject: Merge pull request #494 from ashelly/homing-alarm

Alarm if limits engaged on homing start.

----------------
Date: 2014-09-20
Author: Sonny Jeon
Subject: Merge pull request #493 from alpharesearch/edge

If variable spindle is defined print S value via $G command.

----------------
Date: 2014-09-20
Author: Sonny Jeon
Subject: Minor settings number overflow bug fix.

- The `x` in `$x=val` would overflow when a value larger than 255 was
entered and passed to Grbl. This resulted with unintended parameters
being set by the overflow value. To fix, simply check for values larger
than 255 and error out.


----------------
Date: 2014-09-17
Author: ashelly
Subject: No false alarm if other bits in port are set.

----------------
Date: 2014-09-17
Author: Markus Schulz
Subject: If variable spindle is defined print S value via $G command.


----------------
Date: 2014-09-14
Author: Elijah Insua
Subject: utilize MOTION_MODE_PROBE_NO_ERROR


----------------
Date: 2014-09-14
Author: Elijah Insua
Subject: install G38.{3,4,5}


----------------
Date: 2014-09-14
Author: Elijah Insua
Subject: add MOTION_MODE_PROBE_NO_ERROR


----------------
Date: 2014-09-08
Author: ashelly
Subject: Alarm if limits engaged on homing