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planner.h - buffers movement commands and manages the acceleration profile plan
Part of Grbl
Copyright (c) 2009-2011 Simen Svale Skogsrud
Copyright (c) 2011 Sungeun K. Jeon
Grbl is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Grbl is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Grbl. If not, see <>.
#ifndef planner_h
#define planner_h
#include <inttypes.h>
// This struct is used when buffering the setup for each linear movement "nominal" values are as specified in
// the source g-code and may never actually be reached if acceleration management is active.
typedef struct {
// Fields used by the bresenham algorithm for tracing the line
uint8_t direction_bits; // The direction bit set for this block (refers to *_DIRECTION_BIT in config.h)
uint32_t steps_x, steps_y, steps_z; // Step count along each axis
int32_t step_event_count; // The number of step events required to complete this block
// Fields used by the motion planner to manage acceleration
double nominal_speed; // The nominal speed for this block in mm/min
double entry_speed; // Entry speed at previous-current junction in mm/min
double max_entry_speed; // Maximum allowable junction entry speed in mm/min
double millimeters; // The total travel of this block in mm
uint8_t recalculate_flag; // Planner flag to recalculate trapezoids on entry junction
uint8_t nominal_length_flag; // Planner flag for nominal speed always reached
// Settings for the trapezoid generator
uint32_t initial_rate; // The step rate at start of block
uint32_t final_rate; // The step rate at end of block
int32_t rate_delta; // The steps/minute to add or subtract when changing speed (must be positive)
uint32_t accelerate_until; // The index of the step event on which to stop acceleration
uint32_t decelerate_after; // The index of the step event on which to start decelerating
uint32_t nominal_rate; // The nominal step rate for this block in step_events/minute
} block_t;
// Initialize the motion plan subsystem
void plan_init();
// Add a new linear movement to the buffer. x, y and z is the signed, absolute target position in
// millimaters. Feed rate specifies the speed of the motion. If feed rate is inverted, the feed
// rate is taken to mean "frequency" and would complete the operation in 1/feed_rate minutes.
void plan_buffer_line(double x, double y, double z, double feed_rate, uint8_t invert_feed_rate);
// Called when the current block is no longer needed. Discards the block and makes the memory
// availible for new blocks.
void plan_discard_current_block();
// Gets the current block. Returns NULL if buffer empty
block_t *plan_get_current_block();
// Reset the position vector
void plan_set_current_position(double x, double y, double z);