ManuelW/grbl-LPC-CoreXY
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refactored block buffer into separate module motion_plan pending the addition of the actual look ahead planner

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Simen Svale Skogsrud
2011-01-14 16:45:18 +01:00
parent b628a4aabf
commit 49a16cb777
21 changed files with 163 additions and 146 deletions
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78
stepper.c
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@ -1,8 +1,8 @@
/*
stepper.c - stepper motor interface
stepper.c - stepper motor driver: executes motion plans using stepper motors
Part of Grbl
Copyright (c) 2009 Simen Svale Skogsrud
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
@ -29,49 +29,20 @@
#include <util/delay.h>
#include "nuts_bolts.h"
#include <avr/interrupt.h>
#include "motion_plan.h"
#include "wiring_serial.h"
// Pick a suitable block-buffer size
#ifdef __AVR_ATmega328P__
#define BLOCK_BUFFER_SIZE 40 // Atmega 328 has one full kilobyte of extra RAM!
#else
#define BLOCK_BUFFER_SIZE 10
#endif
void set_step_events_per_minute(uint32_t steps_per_minute);
#define ENABLE_STEPPER_DRIVER_INTERRUPT() TIMSK1 |= (1<<OCIE1A)
#define DISABLE_STEPPER_DRIVER_INTERRUPT() TIMSK1 &= ~(1<<OCIE1A)
#define ACCELERATION_TICKS_PER_SECOND 10
#define MINIMAL_STEP_RATE (ACCELERATION_TICKS_PER_SECOND*5)
#define CYCLES_PER_ACCELERATION_TICK ((TICKS_PER_MICROSECOND*1000000)/ACCELERATION_TICKS_PER_SECOND)
// 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 {
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
// Values used for acceleration management
double speed_x, speed_y, speed_z; // Nominal mm/minute for each axis
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
};
struct Block block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instructions
volatile int block_buffer_head = 0; // Index of the next block to be pushed
volatile int block_buffer_tail = 0; // Index of the block to process now
struct Block *current_block; // A convenience pointer to the block currently being traced
// Variables used by The Stepper Driver Interrupt
uint8_t out_bits; // The next stepping-bits to be output
struct Block *current_block; // A pointer to the block currently being traced
int32_t counter_x,
counter_y,
counter_z; // counter variables for the bresenham line tracer
@ -106,46 +77,9 @@ uint16_t trapezoid_stage_ticks;
uint32_t trapezoid_rate;
int16_t trapezoid_delta;
inline uint32_t estimate_acceleration_distance(int32_t current_rate, int32_t target_rate, int32_t acceleration) {
return((target_rate*target_rate-current_rate*current_rate)/(2*acceleration));
}
inline uint32_t estimate_acceleration_ticks(int32_t start_rate, int32_t acceleration_per_tick, int32_t step_events) {
return(
round(
(sqrt(2*acceleration_per_tick*step_events+(start_rate*start_rate))-start_rate)/
acceleration_per_tick));
}
// Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
// In practice both factors must be in the range 0 ... 1.0
void calculate_trapezoid_for_block(struct Block *block, double entry_factor, double exit_factor) {
block->initial_rate = max(round(block->nominal_rate*entry_factor),MINIMAL_STEP_RATE);
int32_t final_rate = max(round(block->nominal_rate*entry_factor),MINIMAL_STEP_RATE);
int32_t acceleration_per_second = block->rate_delta*ACCELERATION_TICKS_PER_SECOND;
int32_t acceleration_steps =
estimate_acceleration_distance(block->initial_rate, block->nominal_rate, acceleration_per_second);
int32_t decelleration_steps =
estimate_acceleration_distance(block->nominal_rate, final_rate, -acceleration_per_second);
// Check if the acceleration and decelleration periods overlap. In that case nominal_speed will
// never be reached but that's okay. Just truncate both periods proportionally so that they
// fit within the allotted step events.
int32_t plateau_steps = block->step_event_count-acceleration_steps-decelleration_steps;
if (plateau_steps < 0) {
int32_t half_overlap_region = abs(plateau_steps)/2;
plateau_steps = 0;
acceleration_steps = max(acceleration_steps-half_overlap_region,0);
decelleration_steps = max(decelleration_steps-half_overlap_region,0);
}
block->accelerate_ticks = estimate_acceleration_ticks(block->initial_rate, block->rate_delta, acceleration_steps);
if (plateau_steps) {
block->plateau_ticks = round(1.0*plateau_steps/(block->nominal_rate*ACCELERATION_TICKS_PER_SECOND));
} else {
block->plateau_ticks = 0;
}
}
// Call this when a new block is started
// Initializes the trapezoid generator from the current block. Called whenever a new
// block begins.
inline void reset_trapezoid_generator() {
trapezoid_stage = TRAPEZOID_STAGE_ACCELERATING;
trapezoid_stage_ticks = current_block->accelerate_ticks;