grbl/stepper_plan.h

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3.8 KiB
C

/*
stepper_plan.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/>.
*/
#ifndef stepper_plan_h
#define stepper_plan_h
#include <inttypes.h>
// Pick a suitable block-buffer size
#define BLOCK_BUFFER_SIZE 20 // Atmega 328 has one full kilobyte of extra RAM!
// 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
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
// Debug fields, PLEASE REMOVE
uint32_t exit_rate;
} block_t;
extern block_t block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instructions
extern volatile int block_buffer_head; // Index of the next block to be pushed
extern volatile int block_buffer_tail; // Index of the block to process now
// Initialize the motion plan subsystem
void plan_init();
// Do not call directly unless you are writing a motor driver. In current iteration this is called by
// st_buffer_line which also wakes up the stepper subsystem.
// Add a new linear movement to the buffer. steps_x, _y and _z is the signed, relative motion in
// steps. Microseconds specify how many microseconds the move should take to perform. To aid acceleration
// calculation the caller must also provide the physical length of the line in millimeters.
void plan_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t microseconds, double millimeters);
// Enables acceleration-management for upcoming blocks
void plan_enable_acceleration_management();
// Disables acceleration-management for upcoming blocks
void plan_disable_acceleration_management();
#endif