ManuelW/grbl-LPC-CoreXY
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minor edits after verifying refactored grbl on real hardware

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Simen Svale Skogsrud
2010-03-04 21:18:55 +01:00
parent b9c3ea02fb
commit 58ad1ba509
7 changed files with 24 additions and 26 deletions
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31
stepper.c
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@ -46,11 +46,11 @@ volatile int line_buffer_head = 0;
volatile int line_buffer_tail = 0;
// Variables used by SIG_OUTPUT_COMPARE1A
uint8_t out_bits;
struct Line *current_line;
volatile int32_t counter_x, counter_y, counter_z;
uint32_t iterations;
volatile busy;
uint8_t out_bits; // The next stepping-bits to be output
struct Line *current_line; // A pointer to the line currently being traced
volatile int32_t counter_x, counter_y, counter_z; // counter variables for the bresenham line tracer
uint32_t iterations; // The number of iterations left to complete the current_line
volatile busy; // TRUE when SIG_OUTPUT_COMPARE1A is being serviced. Used to avoid retriggering that handler.
void config_step_timer(uint32_t microseconds);
@ -62,8 +62,7 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
// If the buffer is full: good! That means we are well ahead of the robot.
// Nap until there is room in the buffer.
while(line_buffer_tail == next_buffer_head) { sleep_mode(); }
// setup line
// Setup line record
struct Line *line = &line_buffer[line_buffer_head];
line->steps_x = labs(steps_x);
line->steps_y = labs(steps_y);
@ -83,28 +82,26 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
TIMSK1 |= (1<<OCIE1A);
}
// This timer interrupt is executed at the pace set with st_buffer_pace. It pops one instruction from
// This timer interrupt is executed at the rate set with config_step_timer. It pops one instruction from
// the line_buffer, executes it. Then it starts timer2 in order to reset the motor port after
// five microseconds.
SIGNAL(SIG_OUTPUT_COMPARE1A)
{
if(busy){ return; } // The busy-flag is used to avoid retriggering this interrupt.
if(busy){ return; } // The busy-flag is used to avoid reentering this interrupt
PORTD |= (1<<3);
// Set the direction pins a cuple 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
// Reset step pulse reset timer so that SIG_OVERFLOW2 can reset the signal after
// exactly STEP_PULSE_MICROSECONDS microseconds.
TCNT2 = -(((STEP_PULSE_MICROSECONDS-2)*TICKS_PER_MICROSECOND)/8);
busy = TRUE;
sei();
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
// and reset the stepper signal even before this handler is done. Needed
// to generate a clean stepper-signal in the event that this is going to be a time consuming
// time around in this interrupt e.g. if we just completed a line and need to
// set up another.
// at exactly the right time even if we occasionally spend a lot of time inside this handler.
// If there is no current line, attempt to pop one from the buffer
if (current_line == NULL) {
@ -115,7 +112,7 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
// Retrieve a new line and get ready to step it
current_line = &line_buffer[line_buffer_tail];
config_step_timer(current_line->rate);
counter_x = -(current_line->maximum_steps/2);
counter_x = -(current_line->maximum_steps >> 1);
counter_y = counter_x;
counter_z = counter_x;
iterations = current_line->maximum_steps;
@ -213,7 +210,7 @@ void st_flush()
sei();
}
// Configures the prescaler and ceiling of timer 1 to produce the given pace as accurately as possible.
// Configures the prescaler and ceiling of timer 1 to produce the given rate as accurately as possible.
void config_step_timer(uint32_t microseconds)
{
uint32_t ticks = microseconds*TICKS_PER_MICROSECOND;