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

Planner function call fix. More clean up.

Browse Source
This commit is contained in:
Sonny Jeon
2013-10-29 18:55:55 -06:00
parent 27297d444b
commit 0ac6c87196
3 changed files with 115 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
stepper.c
View File

@ -39,8 +39,8 @@
#define SEGMENT_NOOP 0
#define SEGMENT_END_OF_BLOCK bit(0)
#define SEGMENT_ACCEL bit(1)
#define SEGMENT_DECEL bit(2)
#define RAMP_CHANGE_ACCEL bit(1)
#define RAMP_CHANGE_DECEL bit(2)
#define MINIMUM_STEPS_PER_SEGMENT 1 // Don't change
@ -76,7 +76,7 @@ static stepper_t st;
// the number of accessible stepper buffer segments (SEGMENT_BUFFER_SIZE-1).
typedef struct {
int32_t step_events_remaining; // Tracks step event count for the executing planner block
uint32_t dist_next_step; // Scaled distance to next step
uint32_t dist_per_step; // Scaled distance to next step
uint32_t initial_rate; // Initialized step rate at re/start of a planner block
uint32_t nominal_rate; // The nominal step rate for this block in step_events/minute
uint32_t rate_delta; // The steps/minute to add or subtract when changing speed (must be positive)
@ -254,7 +254,7 @@ ISR(TIMER2_COMPA_vect)
st.counter_z = st.counter_x;
// Initialize inverse time, step rate data, and acceleration ramp counters
st.counter_dist = st_current_data->dist_next_step; // dist_next_step always greater than ramp_rate.
st.counter_dist = st_current_data->dist_per_step; // dist_per_step always greater than ramp_rate.
st.ramp_rate = st_current_data->initial_rate;
st.counter_ramp = ISR_TICKS_PER_ACCELERATION_TICK/2; // Initialize ramp counter via midpoint rule
st.ramp_type = RAMP_NOOP_CRUISE; // Initialize as no ramp operation. Corrected later if necessary.
@ -265,7 +265,7 @@ ISR(TIMER2_COMPA_vect)
}
// Check if ramp conditions have changed. If so, update ramp counters and control variables.
if ( st_current_segment->flag & (SEGMENT_DECEL | SEGMENT_ACCEL) ) {
if ( st_current_segment->flag & (RAMP_CHANGE_DECEL | RAMP_CHANGE_ACCEL) ) {
/* Compute correct ramp count for a ramp change. Upon a switch from acceleration to deceleration,
or vice-versa, the new ramp count must be set to trigger the next acceleration tick equal to
the number of ramp ISR ticks counted since the last acceleration tick. This is ensures the
@ -274,7 +274,7 @@ ISR(TIMER2_COMPA_vect)
as mandated by the mid-point rule. For the latter conditions, the ramp count have been
initialized such that the following computation is still correct. */
st.counter_ramp = ISR_TICKS_PER_ACCELERATION_TICK-st.counter_ramp;
if ( st_current_segment->flag & SEGMENT_DECEL ) { st.ramp_type = RAMP_DECEL; }
if ( st_current_segment->flag & RAMP_CHANGE_DECEL ) { st.ramp_type = RAMP_DECEL; }
else { st.ramp_type = RAMP_ACCEL; }
}
@ -319,7 +319,7 @@ ISR(TIMER2_COMPA_vect)
// Execute Bresenham step event, when it's time to do so.
if (st.counter_dist < 0) {
st.counter_dist += st_current_data->dist_next_step; // Reload inverse time counter
st.counter_dist += st_current_data->dist_per_step; // Reload inverse time counter
st.out_bits = pl_current_block->direction_bits; // Reset out_bits and reload direction bits
st.execute_step = true;
@ -493,21 +493,21 @@ void st_cycle_reinitialize()
Currently, the segment buffer conservatively holds roughly up to 40-60 msec of steps.
NOTE: The segment buffer executes a set number of steps over an approximate time period.
If we try to execute over a set time period, it is difficult to guarantee or predict how
many steps will execute over it, especially when the step pulse phasing between the
neighboring segments are kept consistent. Meaning that, if the last segment step pulses
right before its end, the next segment must delay its first pulse so that the step pulses
are consistently spaced apart over time to keep the step pulse train nice and smooth.
Keeping track of phasing and ensuring that the exact number of steps are executed as
defined by the planner block, the related computational overhead gets quickly and
If we try to execute over a fixed time period, it is difficult to guarantee or predict
how many steps will execute over it, especially when the step pulse phasing between the
neighboring segments must also be kept consistent. Meaning that, if the last segment step
pulses right before a segment end, the next segment must delay its first pulse so that the
step pulses are consistently spaced apart over time to keep the step pulse train nice and
smooth. Keeping track of phasing and ensuring that the exact number of steps are executed
as defined by the planner block, the related computational overhead can get quickly and
prohibitively expensive, especially in real-time.
Since the stepper algorithm automatically takes care of the step pulse phasing with
its ramp and inverse time counters, we don't have to explicitly and expensively track the
exact number of steps, time, or phasing of steps. All we need to do is approximate
the number of steps in each segment such that the segment buffer has enough execution time
for the main program to do what it needs to do and refill it when it has time. In other
words, we just need to compute a cheap approximation of the current velocity and the
number of steps over it.
its ramp and inverse time counters by retaining the count remainders, we don't have to
explicitly and expensively track and synchronize the exact number of steps, time, and
phasing of steps. All we need to do is approximate the number of steps in each segment
such that the segment buffer has enough execution time for the main program to do what
it needs to do and refill it when it comes back. In other words, we just need to compute
a cheap approximation of the current velocity and the number of steps over it.
*/
/*
@ -529,7 +529,7 @@ void st_cycle_reinitialize()
*/
void st_prep_buffer()
{
if (sys.state != STATE_QUEUED) { // Block until a motion state is issued
if (sys.state == STATE_QUEUED) { return; } // Block until a motion state is issued
while (segment_buffer_tail != segment_next_head) { // Check if we need to fill the buffer.
// Initialize new segment
@ -555,7 +555,7 @@ void st_prep_buffer()
st_prep_data->step_events_remaining = last_st_prep_data->step_events_remaining;
st_prep_data->rate_delta = last_st_prep_data->rate_delta;
st_prep_data->dist_next_step = last_st_prep_data->dist_next_step;
st_prep_data->dist_per_step = last_st_prep_data->dist_per_step;
st_prep_data->nominal_rate = last_st_prep_data->nominal_rate; // TODO: Feedrate overrides recomputes this.
st_prep_data->mm_per_step = last_st_prep_data->mm_per_step;
@ -575,7 +575,7 @@ void st_prep_buffer()
st_prep_data->nominal_rate = ceil(sqrt(pl_prep_block->nominal_speed_sqr)*(INV_TIME_MULTIPLIER/(60.0*ISR_TICKS_PER_SECOND))); // (mult*mm/isr_tic)
st_prep_data->rate_delta = ceil(pl_prep_block->acceleration*
((INV_TIME_MULTIPLIER/(60.0*60.0))/(ISR_TICKS_PER_SECOND*ACCELERATION_TICKS_PER_SECOND))); // (mult*mm/isr_tic/accel_tic)
st_prep_data->dist_next_step = ceil((pl_prep_block->millimeters*INV_TIME_MULTIPLIER)/pl_prep_block->step_event_count); // (mult*mm/step)
st_prep_data->dist_per_step = ceil((pl_prep_block->millimeters*INV_TIME_MULTIPLIER)/pl_prep_block->step_event_count); // (mult*mm/step)
// TODO: Check if we really need to store this.
st_prep_data->mm_per_step = pl_prep_block->millimeters/pl_prep_block->step_event_count;
@ -593,8 +593,8 @@ void st_prep_buffer()
// Calculate the planner block velocity profile type, determine deceleration point, and initial ramp.
float mm_decelerate_after = plan_calculate_velocity_profile(pl_prep_index);
st_prep_data->decelerate_after = ceil( mm_decelerate_after/st_prep_data->mm_per_step );
if (st_prep_data->decelerate_after > 0) { // If 0, SEGMENT_DECEL flag is set later.
if (st_prep_data->initial_rate != st_prep_data->nominal_rate) { prep_segment->flag = SEGMENT_ACCEL; }
if (st_prep_data->decelerate_after > 0) { // If 0, RAMP_CHANGE_DECEL flag is set later.
if (st_prep_data->initial_rate != st_prep_data->nominal_rate) { prep_segment->flag = RAMP_CHANGE_ACCEL; }
}
}
@ -604,9 +604,9 @@ void st_prep_buffer()
// Approximate the velocity over the new segment using the already computed rate values.
// NOTE: This assumes that each segment will have an execution time roughly equal to every ACCELERATION_TICK.
// We do this to minimize memory and computational requirements. However, this could easily be replaced with
// a more exact approximation or have a unique time per segment, if CPU and memory overhead allows.
// a more exact approximation or have an user-defined time per segment, if CPU and memory overhead allows.
if (st_prep_data->decelerate_after <= 0) {
if (st_prep_data->decelerate_after == 0) { prep_segment->flag = SEGMENT_DECEL; } // Set segment deceleration flag
if (st_prep_data->decelerate_after == 0) { prep_segment->flag = RAMP_CHANGE_DECEL; } // Set segment deceleration flag
else { st_prep_data->current_approx_rate -= st_prep_data->rate_delta; }
if (st_prep_data->current_approx_rate < st_prep_data->rate_delta) { st_prep_data->current_approx_rate >>= 1; }
} else {
@ -618,10 +618,12 @@ void st_prep_buffer()
}
}
// TODO: Look into replacing the following dist_per_step divide with multiplying its inverse to save cycles.
// Compute the number of steps in the prepped segment based on the approximate current rate.
// NOTE: The dist_next_step divide cancels out the INV_TIME_MULTIPLIER and converts the rate value to steps.
// NOTE: The dist_per_step divide cancels out the INV_TIME_MULTIPLIER and converts the rate value to steps.
prep_segment->n_step = ceil(max(MINIMUM_STEP_RATE,st_prep_data->current_approx_rate)*
(ISR_TICKS_PER_SECOND/ACCELERATION_TICKS_PER_SECOND)/st_prep_data->dist_next_step);
(ISR_TICKS_PER_SECOND/ACCELERATION_TICKS_PER_SECOND)/st_prep_data->dist_per_step);
// NOTE: Ensures it moves for very slow motions, but MINIMUM_STEP_RATE should always set this too. Perhaps
// a compile-time check to see if MINIMUM_STEP_RATE is set high enough is all that is needed.
prep_segment->n_step = max(prep_segment->n_step,MINIMUM_STEPS_PER_SEGMENT);
@ -668,7 +670,6 @@ void st_prep_buffer()
// printString(" ");
}
}
}
uint8_t st_get_prep_block_index()