planner.h

/*
  planner.h - buffers movement commands and manages the acceleration profile plan
  Part of Grbl

  Copyright (c) 2009-2011 Simen Svale Skogsrud

  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
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  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 <http://www.gnu.org/licenses/>.
*/

// This module is to be considered a sub-module of stepper.c. Please don't include 
// this file from any other module.

#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
    uint32_t steps_x, steps_y, steps_z;	// Step count along each axis
    uint8_t direction_bits;	// The direction bit set for this block (refers to *_DIRECTION_BIT in config.h)
    int32_t step_event_count;	// The number of step events required to complete this block
    uint32_t nominal_rate;	// The nominal step rate for this block in step_events/minute

    // Fields used by the motion planner to manage acceleration
    double speed_x, speed_y, speed_z;	// Nominal mm/minute for each axis
    double nominal_speed;	// The nominal speed for this block in mm/min  
    double millimeters;		// The total travel of this block in mm
    double entry_factor;	// The factor representing the change in speed at the start of this trapezoid.
    // (The end of the curren speed trapezoid is defined by the entry_factor of the
    // next block)

    // Settings for the trapezoid generator
    uint32_t initial_rate;	// The jerk-adjusted step rate at start of block  
    uint32_t final_rate;	// The minimal rate at exit
    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

} 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,
		      int 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();

// Enables or disables acceleration-management for upcoming blocks
void plan_set_acceleration_manager_enabled(int enabled);

// Is acceleration-management currently enabled?
int plan_is_acceleration_manager_enabled();

#endif