pcomplete, fully untested, support for accelleration management with look ahead optimization, finally

stepper_plan.h

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+/*
+  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
+#ifdef __AVR_ATmega328P__
+#define BLOCK_BUFFER_SIZE 20   // Atmega 328 has one full kilobyte of extra RAM!
+#else
+#define BLOCK_BUFFER_SIZE 10
+#endif
+
+// 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.
+struct Block {
+  // 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;
+  double entry_factor;                // The factors representing the change in speed at the start of the trapezoid
+  uint32_t initial_rate;              // The jerk-adjusted step rate at start of block
+  int16_t rate_delta;                 // The steps/minute to add or subtract when changing speed (must be positive)
+  uint16_t accelerate_ticks;          // The number of acceleration-ticks to accelerate 
+  uint16_t plateau_ticks;             // The number of acceleration-ticks to maintain top speed
+};
+      
+extern struct Block 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