ManuelW/grbl-LPC-CoreXY
1
0
Fork 0
Code Issues Pull Requests Releases 1 Wiki Activity

Third time's a charm! No more deceleration issues! Updated grbl version and settings. General cleanup.

Browse Source 
- Fleshed out the original idea to completely remove the long slope at
the end of deceleration issue. This third time should absolutely
eliminate it.
- Changed the acceleration setting to kept as mm/min^2 internally,
since this was creating unneccessary additional computation in the
planner. Human readable value kept at mm/sec^2.
- Updated grbl version 0.7d and settings version to 4. NOTE: Please
check settings after update. These may have changed, but shouldn't.
- Before updating the new features (pause, e-stop, federate override,
etc), the edge branch will soon be merged with the master, barring any
immediate issues that people may have, and the edge branch will be the
testing ground for the new grbl version 0.8.
This commit is contained in:
Sonny Jeon
2011-10-11 20:51:04 -06:00
parent c98ff4cc2e
commit 9141ad2825
10 changed files with 270 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
stepper.c
View File

@ -3,7 +3,7 @@
Part of Grbl
Copyright (c) 2009-2011 Simen Svale Skogsrud
Modifications Copyright (c) 2011 Sungeun K. Jeon
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
@ -56,6 +56,8 @@ static uint32_t cycles_per_step_event; // The number of machine cycles be
static uint32_t trapezoid_tick_cycle_counter; // The cycles since last trapezoid_tick. Used to generate ticks at a steady
// pace without allocating a separate timer
static uint32_t trapezoid_adjusted_rate; // The current rate of step_events according to the trapezoid generator
static uint32_t min_safe_rate; // Minimum safe rate for full deceleration rate reduction step. Otherwise halves step_rate.
static uint8_t cycle_start; // Cycle start flag to indicate program start and block processing.
// __________________________
// /| |\ _________________ ^
@ -76,14 +78,20 @@ static uint32_t trapezoid_adjusted_rate; // The current rate of step_events
static void set_step_events_per_minute(uint32_t steps_per_minute);
// Stepper state initialization
void st_wake_up() {
// Initialize stepper output bits
out_bits = (0) ^ (settings.invert_mask);
// Enable steppers by resetting the stepper disable port
STEPPERS_DISABLE_PORT &= ~(1<<STEPPERS_DISABLE_BIT);
// Enable stepper driver interrupt
TIMSK1 |= (1<<OCIE1A);
}
// Stepper shutdown
static void st_go_idle() {
// Cycle finished. Set flag to false.
cycle_start = false;
// Force stepper dwell to lock axes for a defined amount of time to ensure the axes come to a complete
// stop and not drift from residual inertial forces at the end of the last movement.
#if STEPPER_IDLE_LOCK_TIME
@ -98,7 +106,8 @@ static void st_go_idle() {
// Initializes the trapezoid generator from the current block. Called whenever a new
// block begins.
static void trapezoid_generator_reset() {
trapezoid_adjusted_rate = current_block->initial_rate;
trapezoid_adjusted_rate = current_block->initial_rate;
min_safe_rate = current_block->rate_delta + (current_block->rate_delta >> 1); // 1.5 x rate_delta
trapezoid_tick_cycle_counter = CYCLES_PER_ACCELERATION_TICK/2; // Start halfway for midpoint rule.
set_step_events_per_minute(trapezoid_adjusted_rate); // Initialize cycles_per_step_event
}
@ -116,23 +125,24 @@ static uint8_t iterate_trapezoid_cycle_counter() {
}
}
// "The Stepper Driver Interrupt" - This timer interrupt is the workhorse of Grbl. It is executed at the rate set with
// "The Stepper Driver Interrupt" - This timer interrupt is the workhorse of Grbl. It is executed at the rate set with
// config_step_timer. It pops blocks from the block_buffer and executes them by pulsing the stepper pins appropriately.
// It is supported by The Stepper Port Reset Interrupt which it uses to reset the stepper port after each pulse.
// The bresenham line tracer algorithm controls all three stepper outputs simultaneously with these two interrupts.
SIGNAL(TIMER1_COMPA_vect)
{
// TODO: Check if the busy-flag can be eliminated by just disabeling this interrupt while we are in it
// TODO: Check if the busy-flag can be eliminated by just disabling this interrupt while we are in it
if(busy){ return; } // The busy-flag is used to avoid reentering this interrupt
// Set the direction pins a cuple of nanoseconds before we step the steppers
// Set the direction pins a couple of nanoseconds before we step the steppers
STEPPING_PORT = (STEPPING_PORT & ~DIRECTION_MASK) | (out_bits & DIRECTION_MASK);
// Then pulse the stepping pins
STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | out_bits;
// Reset step pulse reset timer so that The Stepper Port Reset Interrupt can reset the signal after
// exactly settings.pulse_microseconds microseconds.
TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND)/8);
// TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND)/8);
TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND) >> 3); // Bit shift divide by 8.
busy = true;
sei(); // Re enable interrupts (normally disabled while inside an interrupt handler)
// ((We re-enable interrupts in order for SIG_OVERFLOW2 to be able to be triggered
@ -172,7 +182,7 @@ SIGNAL(TIMER1_COMPA_vect)
counter_z -= current_block->step_event_count;
}
step_events_completed += 1; // Iterate step events
step_events_completed++; // Iterate step events
// While in block steps, check for de/ac-celeration events and execute them accordingly.
if (step_events_completed < current_block->step_event_count) {
@ -205,12 +215,15 @@ SIGNAL(TIMER1_COMPA_vect)
} else {
// Iterate cycle counter and check if speeds need to be reduced.
if ( iterate_trapezoid_cycle_counter() ) {
// NOTE: We will only reduce speed if the result will be > 0. This catches small
// rounding errors that might leave steps hanging after the last trapezoid tick.
// The if statement performs a bit shift multiply by 2 to gauge when to begin
// adjusting the rate by half increments. Prevents the long slope at the end of
// deceleration issue that occurs in certain cases.
if ((trapezoid_adjusted_rate << 1) > current_block->rate_delta) {
// NOTE: We will only do a full speed reduction if the result is more than the minimum safe
// rate, initialized in trapezoid reset as 1.5 x rate_delta. Otherwise, reduce the speed by
// half increments until finished. The half increments are guaranteed not to exceed the
// CNC acceleration limits, because they will never be greater than rate_delta. This catches
// small errors that might leave steps hanging after the last trapezoid tick or a very slow
// step rate at the end of a full stop deceleration in certain situations. The half rate
// reductions should only be called once or twice per block and create a nice smooth
// end deceleration.
if (trapezoid_adjusted_rate > min_safe_rate) {
trapezoid_adjusted_rate -= current_block->rate_delta;
} else {
trapezoid_adjusted_rate >>= 1; // Bit shift divide by 2
@ -235,11 +248,8 @@ SIGNAL(TIMER1_COMPA_vect)
current_block = NULL;
plan_discard_current_block();
}
} else {
// Still no block? Set the stepper pins to low before sleeping.
out_bits = 0;
}
}
out_bits ^= settings.invert_mask; // Apply stepper invert mask
busy=false;
@ -339,3 +349,11 @@ void st_go_home()
limits_go_home();
plan_set_current_position(0,0,0);
}
// Planner external interface to start stepper interrupt and execute the blocks in queue.
void st_cycle_start() {
if (!cycle_start) {
cycle_start = true;
st_wake_up();
}
}