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Merge pull request #6912 from thinkyhead/bf_better_pulse_delay

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Account for dual XYZ in pulse delay cycles estimate
This commit is contained in:
Scott Lahteine 2017-05-31 22:21:47 -05:00 committed by GitHub
commit 155aa62fb0
1 changed files with 49 additions and 13 deletions
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62
Marlin/stepper.cpp
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@ -528,33 +528,69 @@ void Stepper::isr() {
_APPLY_STEP(AXIS)(_INVERT_STEP_PIN(AXIS),0); \
}
/**
* Estimate the number of cycles that the stepper logic already takes
* up between the start and stop of the X stepper pulse.
*
* Currently this uses very modest estimates of around 5 cycles.
* True values may be derived by careful testing.
*
* Once any delay is added, the cost of the delay code itself
* may be subtracted from this value to get a more accurate delay.
* Delays under 20 cycles (1.25µs) will be very accurate, using NOPs.
* Longer delays use a loop. The resolution is 8 cycles.
*/
#if HAS_X_STEP
#define _COUNT_STEPPERS_1 1
#define _CYCLE_APPROX_1 5
#else
#define _COUNT_STEPPERS_1 0
#define _CYCLE_APPROX_1 0
#endif
#if ENABLED(X_DUAL_STEPPER_DRIVERS)
#define _CYCLE_APPROX_2 _CYCLE_APPROX_1 + 4
#else
#define _CYCLE_APPROX_2 _CYCLE_APPROX_1
#endif
#if HAS_Y_STEP
#define _COUNT_STEPPERS_2 _COUNT_STEPPERS_1 + 1
#define _CYCLE_APPROX_3 _CYCLE_APPROX_2 + 5
#else
#define _COUNT_STEPPERS_2 _COUNT_STEPPERS_1
#define _CYCLE_APPROX_3 _CYCLE_APPROX_2
#endif
#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
#define _CYCLE_APPROX_4 _CYCLE_APPROX_3 + 4
#else
#define _CYCLE_APPROX_4 _CYCLE_APPROX_3
#endif
#if HAS_Z_STEP
#define _COUNT_STEPPERS_3 _COUNT_STEPPERS_2 + 1
#define _CYCLE_APPROX_5 _CYCLE_APPROX_4 + 5
#else
#define _COUNT_STEPPERS_3 _COUNT_STEPPERS_2
#define _CYCLE_APPROX_5 _CYCLE_APPROX_4
#endif
#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
#define _CYCLE_APPROX_6 _CYCLE_APPROX_5 + 4
#else
#define _CYCLE_APPROX_6 _CYCLE_APPROX_5
#endif
#if DISABLED(ADVANCE) && DISABLED(LIN_ADVANCE)
#define _COUNT_STEPPERS_4 _COUNT_STEPPERS_3 + 1
#if ENABLED(MIXING_EXTRUDER)
#define _CYCLE_APPROX_7 _CYCLE_APPROX_6 + (MIXING_STEPPERS) * 6
#else
#define _COUNT_STEPPERS_4 _COUNT_STEPPERS_3
#define _CYCLE_APPROX_7 _CYCLE_APPROX_6 + 5
#endif
#else
#define _CYCLE_APPROX_7 _CYCLE_APPROX_6
#endif
#define CYCLES_EATEN_XYZE ((_COUNT_STEPPERS_4) * 5)
#define CYCLES_EATEN_XYZE _CYCLE_APPROX_7
#define EXTRA_CYCLES_XYZE (STEP_PULSE_CYCLES - (CYCLES_EATEN_XYZE))
// If a minimum pulse time was specified get the timer 0 value
// which increments every 4µs on 16MHz and every 3.2µs on 20MHz.
// Two or 3 counts of TCNT0 should be a sufficient delay.
/**
* If a minimum pulse time was specified get the timer 0 value.
*
* TCNT0 has an 8x prescaler, so it increments every 8 cycles.
* That's every 0.5µs on 16MHz and every 0.4µs on 20MHz.
* 20 counts of TCNT0 -by itself- is a good pulse delay.
* 10µs = 160 or 200 cycles.
*/
#if EXTRA_CYCLES_XYZE > 20
uint32_t pulse_start = TCNT0;
#endif
@ -627,7 +663,7 @@ void Stepper::isr() {
break;
}
// For minimum pulse time wait before stopping pulses
// For minimum pulse time wait after stopping pulses also
#if EXTRA_CYCLES_XYZE > 20
if (i) while (EXTRA_CYCLES_XYZE > (uint32_t)(TCNT0 - pulse_start) * (INT0_PRESCALER)) { /* nada */ }
#elif EXTRA_CYCLES_XYZE > 0