ManuelW/grbl-LPC-CoreXY
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Minor prescalar optimization. Changed up some defines.

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This commit is contained in:
Sonny Jeon
2012-09-21 17:55:02 -06:00
parent 420c7c2584
commit 4224ab4999
4 changed files with 27 additions and 28 deletions
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26
stepper.c
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@ -91,7 +91,7 @@ static void st_wake_up()
// Initialize stepper output bits
out_bits = (0) ^ (settings.invert_mask);
// Initialize step pulse timing from settings. Here to ensure updating after re-writing.
#if STEP_PULSE_DELAY > 0
#ifdef STEP_PULSE_DELAY
// Set total step pulse time after direction pin set. Ad hoc computation from oscilloscope.
step_pulse_time = -(((settings.pulse_microseconds+STEP_PULSE_DELAY-2)*TICKS_PER_MICROSECOND) >> 3);
// Set delay between direction pin write and step command.
@ -113,7 +113,7 @@ void st_go_idle()
TIMSK1 &= ~(1<<OCIE1A);
// 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 > 0
#ifdef STEPPER_IDLE_LOCK_TIME
_delay_ms(STEPPER_IDLE_LOCK_TIME);
#endif
// Disable steppers by setting stepper disable
@ -145,7 +145,7 @@ ISR(TIMER1_COMPA_vect)
// 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
#if STEP_PULSE_DELAY > 0
#ifdef STEP_PULSE_DELAY
step_bits = (STEPPING_PORT & ~STEP_MASK) | out_bits; // Store out_bits to prevent overwriting.
#else // Normal operation
STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | out_bits;
@ -314,7 +314,7 @@ ISR(TIMER2_OVF_vect)
TCCR2B = 0; // Disable Timer2 to prevent re-entering this interrupt when it's not needed.
}
#if STEP_PULSE_DELAY > 0
#ifdef STEP_PULSE_DELAY
// This interrupt is used only when STEP_PULSE_DELAY is enabled. Here, the step pulse is
// initiated after the STEP_PULSE_DELAY time period has elapsed. The ISR TIMER2_OVF interrupt
// will then trigger after the appropriate settings.pulse_microseconds, as in normal operation.
@ -358,7 +358,7 @@ void st_init()
TCCR2B = 0; // Disable timer until needed.
TIMSK2 |= (1<<TOIE2);
#if STEP_PULSE_DELAY > 0
#ifdef STEP_PULSE_DELAY
TIMSK2 |= (1<<OCIE2A); // Enable Timer2 Compare Match A interrupt
#endif
@ -371,36 +371,36 @@ void st_init()
static uint32_t config_step_timer(uint32_t cycles)
{
uint16_t ceiling;
uint16_t prescaler;
uint8_t prescaler;
uint32_t actual_cycles;
if (cycles <= 0xffffL) {
ceiling = cycles;
prescaler = 0; // prescaler: 0
prescaler = 1; // prescaler: 0
actual_cycles = ceiling;
} else if (cycles <= 0x7ffffL) {
ceiling = cycles >> 3;
prescaler = 1; // prescaler: 8
prescaler = 2; // prescaler: 8
actual_cycles = ceiling * 8L;
} else if (cycles <= 0x3fffffL) {
ceiling = cycles >> 6;
prescaler = 2; // prescaler: 64
prescaler = 3; // prescaler: 64
actual_cycles = ceiling * 64L;
} else if (cycles <= 0xffffffL) {
ceiling = (cycles >> 8);
prescaler = 3; // prescaler: 256
prescaler = 4; // prescaler: 256
actual_cycles = ceiling * 256L;
} else if (cycles <= 0x3ffffffL) {
ceiling = (cycles >> 10);
prescaler = 4; // prescaler: 1024
prescaler = 5; // prescaler: 1024
actual_cycles = ceiling * 1024L;
} else {
// Okay, that was slower than we actually go. Just set the slowest speed
ceiling = 0xffff;
prescaler = 4;
prescaler = 6;
actual_cycles = 0xffff * 1024;
}
// Set prescaler
TCCR1B = (TCCR1B & ~(0x07<<CS10)) | ((prescaler+1)<<CS10);
TCCR1B = (TCCR1B & ~(0x07<<CS10)) | (prescaler<<CS10);
// Set ceiling
OCR1A = ceiling;
return(actual_cycles);