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.
- Added a new optional compile-time feature for ‘realtime’ (within
50ms) feed rate reporting. When querying for a status report, a new
data value will state the current operating rate. It’s only beta at the
moment and has some kinks to work out.
- Updated the code for printing floating point values to N decimal
places. Generalized the main floating point print code to accept a new
decimal places value and created a set of handler functions to print
certain floating point value types used in Grbl, like position, rates,
coordinate offsets, etc. All of these have different decimal
requirements and change when printed in mm or inches mode.
- Number of decimal places for the different value types can be
re-defined in config.h, but there shouldn’t be a need for this, as
these are physically limited.
- Removed the decimal places settings, as this was now obsoleted by the
new decimal places code.
- The new decimal places code also saves almost 300kB in flash space,
as it’s more efficient.
- 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.
- 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.
- New build info feature. Hidden command ‘$I’ will print the build info
for your Grbl firmware. Users may also write an identifying message
within it via ‘$I=‘ with up to 32 characters. (no more, or else it will
break).
- Adjusted the max number of startup lines to 3. Majority of people
will only need one.
- Fixed a compile error with spindle_control.c. A rogue #endif was
causing problems.
- 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.
- 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!
- Revamped and improved homing cycle. Now tied directly into the main
planner and stepper code, which enables much faster homing seek rates.
Also dropped the compiled flash size by almost 1KB, meaning 1KB more
for other features.
- Refactored config.h. Removed obsolete defines and configuration
options. Moved lots of “advanced” options into the advanced area of the
file.
- Updated defaults.h with the new homing cycle. Also updated the
Sherline 5400 defaults and added the ShapeOko2 defaults per user
submissions.
- Fixed a bug where the individual axes limits on velocity and
acceleration were not working correctly. Caused by abs() returning a
int, rather than a float. Corrected with fabs(). Duh.
- Added build version/date to the Grbl welcome message to help indicate
which version a user is operating on.
- Max travel settings were not being defaulted into the settings EEPROM
correctly. Fixed.
- To stop a single axis during a multi-axes homing move, the stepper
algorithm now has a simple axis lock mask which inhibits the desired
axes from moving. Meaning, if one of the limit switches engages before
the other, we stop that one axes and keep moving the other.
- Pushed limit switch active high option (i.e. NC switches).
- Updated defaults.h to be in-line with the new settings.
- Refactored feed hold handling and step segment buffer to be more
generalized in effort to make adding feedrate overrides easier in the
future. Also made it a little more clean.
- Fixed G18 plane select issue. Now ZX-plane, rather than XZ-plane, per
right hand rule.
- Cleaned some of the system settings by more accurately renaming some
of the variables and removing old obsolete ones.
- Declared serial.c rx_buffer_tail to be volatile. No effect, since
avr-gcc automatically does this during compilation. Helps with porting
when using other compilers.
- Updated version number to v0.9b.
- Updates to README.md
- 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.
- 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.
- 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!
NOTE: This push is a work-in-progress and there are known bugs that
need to be fixed, like homing acceleration being incompatible. Released
for testing. Settings will definitely be overwritten, as new settings
were needed.
- Acceleration independence installed in planner. Each axis can now
have different accelerations and Grbl will maximize the accelerations
depending on the direction its moving. Very useful for users like on
the ShapeOko with vastly different Z-axis properties.
- More planner optimizations and re-factoring. Slightly improved some
of the older calculations, but new acceleration calculations offset
these improvements. Overall no change in processing speed.
- Removed planner nominal length checks. It was arguable whether or not
this improved planner efficiency, especially in the worst case scenario
of arcs.
- Updated readme and changed to markdown format.
- 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
- Removed the dry run switch. It was getting overly complicated for
what it needed to do. In practice, single block mode and feed rate
overrides (coming in next release) does a much better job with dry runs
than 'dry run'.
- Trimmed all of Grbl's messages from help, status, feedback to
settings. Saved 0.6KB+ of flash space that could be used for v0.9
features.
- Removed some settings inits when set. Will depend on user to power
cycle to get some of these to reload.
- Fixed a bug with settings version not re-writing old settings, when
it should. Thanks Alden!
- 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.
(All v0.8 features installed. Still likely buggy, but now thourough
testing will need to start to squash them all. As soon as we're done,
this will be pushed to master and v0.9 development will be started.
Please report ANY issues to us so we can get this rolled out ASAP.)
- User startup script! A user can now save one (up to 5 as compile-time
option) block of g-code in EEPROM memory. This will be run everytime
Grbl resets. Mainly to be used as a way to set your preferences, like
G21, G54, etc.
- New dry run and check g-code switches. Dry run moves ALL motions at
rapids rate ignoring spindle, coolant, and dwell commands. For rapid
physical proofing of your code. The check g-code switch ignores all
motion and provides the user a way to check if there are any errors in
their program that Grbl may not like.
- Program restart! (sort of). Program restart is typically an advanced
feature that allows users to restart a program mid-stream. The check
g-code switch can perform this feature by enabling the switch at the
start of the program, and disabling it at the desired point with some
minimal changes.
- New system state variable. This state variable tracks all of the
different state processes that Grbl performs, i.e. cycle start, feed
hold, homing, etc. This is mainly for making managing of these task
easier and more clear.
- Position lost state variable. Only when homing is enabled, Grbl will
refuse to move until homing is completed and position is known. This is
mainly for safety. Otherwise, it will let users fend for themselves.
- Moved the default settings defines into config.h. The plan is to
eventually create a set of config.h's for particular as-built machines
to help users from doing it themselves.
- Moved around misc defines into .h files. And lots of other little
things.
NOTE: Another incremental update. Likely buggy, still a ways to go
before everything is installed, such as startup blocks.
- Changed the '$' command to print help. '$$' now prints Grbl settings.
The help now instructs the user of runtime commands, switch toggling,
homing, etc. Jogging will be added to these in v0.9.
- Added switches: block delete, opt stop, and single block mode.
- Now can print the g-code parser state and persistent parameters
(coord sys) to view what Grbl has internally.
- Made the gc struct in the g-code parser global to be able to print
the states. Also moved coordinate system tracking from sys to gc struct.
- Changed up the welcome flag and updated version to v0.8c.
- Removed spindle speed from gcode parser. Not used.
(NOTE: This push is likely buggy so proceed with caution. Just
uploading to let people know where we're going.)
- New report.c module. Moved all feedback functions into this module to
centralize these processes. Includes realtime status reports, status
messages, feedback messages.
- Official support 6 work coordinate systems (G54-G59), which are
persistently held in EEPROM memory.
- New g-code support: G28.1, G30.1 stores current machine position as a
home position into EEPROM. G10 L20 Px stores current machine position
into work coordinates without needing to explicitly send XYZ words.
- Homing performed with '$H' command. G28/G30 no longer start the
homing cycle. This is how it's supposed to be.
- New settings: Stepper enable invert and n_arc correction installed.
- Updated and changed up some limits and homing functionality. Pull-off
travel will now move after the homing cycle regardless of hard limits
enabled. Fixed direction of pull-off travel (went wrong way).
- Started on designing an internal Grbl command protocol based on the
'$' settings letter. Commands with non numeric characters after '$'
will perform switch commands, homing cycle, jogging, printing
paramters, etc. Much more to do here.
- Updated README to reflect all of the new features.
- Installed a new 'alarm' method to centralize motion kills across
alarm or reset events. Right now, this is controlled by system abort
and hard limits. But, in the future, a g-code parser error may call
this too as a safety feature.
- Re(re)organized status messages to just print all errors, regardless
from where it was called. This centralizes them into one place.
- Misc messages method installed for any user feedback that is not a
confirmation or error. Mainly so that there is a place to perform
warnings and such.
- New stuff installed and still made the flash size smaller by saving
flash space from clearing out repeated '\r\n' pgmstrings.
- Fixed a bug where hard limits message would print everytime a system
abort was sent.
- Reorganized all of the status message feedback from both the g-code
parser and settings modules to be centralized into two message modules:
status feedback from executing a line and warnings for misc feedback.
- Pulled out the printPgmString() messages in settings.c and placed it
into the new module. (settings_dump() not moved).
- Some other minor edits. Renaming defines, comment updates, etc.
- Thank you statement added for Alden Hart of Synthetos.
- Hard limits option added, which also works with homing by pulling off
the switches to help prevent unintended triggering. Hard limits use a
interrupt to sense a falling edge pin change and immediately go into
alarm mode, which stops everything and forces the user to issue a reset
(Ctrl-x) or reboot.
- Auto cycle start now a configuration option.
- Alarm mode: A new method to kill all Grbl processes in the event of
something catastrophic or potentially catastropic. Just works with hard
limits for now, but will be expanded to include g-code errors (most
likely) and other events.
- Updated status reports to be configurable in inches or mm mode. Much
more to do here, but this is the first step.
- New settings: auto cycle start, hard limit enable, homing direction
mask (which works the same as the stepper mask), homing pulloff
distance (or distance traveled from homed machine zero to prevent
accidental limit trip).
- Minor memory liberation and calculation speed ups.
- Allowed status_message function to be called by others. This is to
centralize all feedback into protocol.c.
- Fixed a bug where line number words 'N' were causing the parser to
error out.
- Allowed homing routine feed rates to move slower than the
MINIMUM_STEP_RATE parameter in config.h.
- Homing performs idle lock at the end of the routine.
- Stepper idle lock time will now not disable the steppers when the
value is set at 255. This is accomodate users who prefer to keep their
axes enabled at all times.
- Moved some defines around to where they need to be.
- printFloat() function execution doubled in speed. This is a precursor
to status reporting, since GUIs may query real-time position rapidly.
- Decimal places added to settings (for now). This may disappear in
future pushes, but here for testing purposes.
- Homing cycle will now cycle twice (spec more/less in config) to
improve repeatability and accuracy by decreasing overshoot.
- New Grbl settings added: Enable/disable homing cycles, homing seek
and feed rates, switch debounce delay, and stepper idle lock time.
- Please note that these settings may change upon the next push, since
there will be more added soon. Grbl *should* not re-write your old
settings, just re-write the new ones. So, make sure you keep these
written down somewhere in case they get lost from a code bug.
- Refactored settings migration to be a little smaller and managable
going forward.
- Limit pin internal pull-resistors now enabled. Normal high operation.
This will be the standard going forward.
- Updated all of the 'double' variable types to 'float' to reflect what
happens when compiled for the Arduino. Also done for compatibility
reasons to @jgeisler0303 's Grbl simulator code.
- G-code parser will now ignore 'E' exponent values, since they are
reserved g-code characters for some machines. Thanks @csdexter!
- The read_double() function was re-written and optimized for use in
Grbl. The strtod() avr lib was removed.
- Added machine position reporting to status queries. This will be
further developed with part positioning/offsets and maintaining
location upon reset.
- System variables refactored into a global struct for better
readability.
- Removed old obsolete Ruby streaming scripts. These were no longer
compatible. Updated Python streaming scripts.
- Fixed printFloat() and other printing functions.
- Decreased planner buffer back to 18 blocks and increased TX serial
buffer to 64 bytes. Need the memory space for future developments.
- Begun adding run-time modes to grbl, where block delete toggle, mm/in
reporting modes, jog modes, etc can be set during runtime. Will be
fleshed out and placed into EEPROM when everything is added.
- ALPHA status. - Multitasking ability with run-time command executions
for real-time control and feedback. - Decelerating feed hold and resume
during operation. - System abort/reset, which immediately kills all
movement and re-initializes grbl. - Re-structured grbl to easily allow
for new features: Status reporting, jogging, backlash compensation. (To
be completed in the following releases.) - Resized TX/RX serial buffers
(32/128 bytes) - Increased planner buffer size to 20 blocks. - Updated
documentation.
- Fleshed out the original idea to completely remove the long slope at
the end of deceleration issue. This third time should absolutely
eliminate it.
- Changed the acceleration setting to kept as mm/min^2 internally,
since this was creating unneccessary additional computation in the
planner. Human readable value kept at mm/sec^2.
- Updated grbl version 0.7d and settings version to 4. NOTE: Please
check settings after update. These may have changed, but shouldn't.
- Before updating the new features (pause, e-stop, federate override,
etc), the edge branch will soon be merged with the master, barring any
immediate issues that people may have, and the edge branch will be the
testing ground for the new grbl version 0.8.
- The long standing issue of a long slope at deceleration is likely
fixed. The stepper program was not tracking and timing the end of
acceleration and start of deceleration exactly and now is fixed to
start and stop on time. Also, to ensure a better acceleration curve fit
used by the planner, the stepper program delays the start of the
accelerations by a half trapezoid tick to employ the midpoint rule. -
Settings version 3 migration (not fully tested, but should work) -
Added a MINIMUM_PLANNER_SPEED user-defined parameter to planner to let
a user change this if problems arise for some reason. - Moved all
user-definable #define parameters into config.h with clear comments on
what they do and recommendations of how to change them. - Minor
housekeeping.
- Serial functions contained quite a few modulo operations that would
be executed with high frequency when streaming. AVR processors are very
slow when operating these. In one test on the Arduino forums, it showed
about a 15x slow down compared to a simple if-then statement. -
Clarified some variable names and types and comments.
- Update grbl version and settings version to automatically reset
eeprom. FYI, this will reset your grbl settings. - Saved
3*BLOCK_BUFFER_SIZE doubles in static memory by removing obsolete
variables: speed_x, speed_y, and speed_z. - Increased buffer size
conservatively to 18 from 16. (Probably can do 20). - Removed expensive!
modulo operator from block indexing function. Reduces significant
computational overhead. - Re-organized some sqrt() calls to be more
efficient during time critical planning cases, rather than non-time
critical. - Minor bug fix in planner max junction velocity logic. -
Simplified arc logic and removed need to multiply for CW or CCW
direction.
- Significant improvements in the planner. Removed or reordered
repetitive and expensive calculations by order of importance:
recalculating unchanged blocks, trig functions [sin(), cos(), tan()],
sqrt(), divides, and multiplications. Blocks long enough for nominal
speed to be guaranteed to be reached ignored by planner. Done by
introducing two uint8_t flags per block. Reduced computational overhead
by an order of magnitude. - Arc motion generation completely
re-written and optimized. Now runs with acceleration planner. Removed
all but one trig function (atan2) from initialization. Streamlined
computations. Segment target locations generated by vector
transformation and small angle approximation. Arc path correction
implemented for accumulated error of approximation and single precision
calculation of Arduino. Bug fix in message passing.
- Junction jerk now re-defined as junction_deviation. The distance from
the junction to the edge of a circle tangent to both previous and
current path lines. The circle radii is used to compute the maximum
junction velocity by centripetal acceleration. More robust and
simplified way to compute jerk. - Fixed bugs related to entry and exit
factors. They were computed based on the current nominal speeds but not
when computing exit factors for neighboring blocks. Removed factors and
replaced with entry speeds only. Factors now only computed for stepper
trapezoid rate conversions. - Misc: Added min(), next_block_index,
prev_block_index functions for clarity.
