ManuelW/grbl-LPC-CoreXY
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minor edits

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This commit is contained in:
Simen Svale Skogsrud 2009-02-11 09:28:40 +01:00
parent 9e6d62e531
commit bf38fae67b
1 changed files with 9 additions and 4 deletions
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13
motion_control.c
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@ -239,7 +239,8 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
// The number of steppings needed to trace this motion is equal to the motion that require the maximum
// amount of steps: the arc or the line:
int32_t maximum_steps = max(linear_steps, arc_steps);
// Initialize the counters to do linear bresenham
// Initialize the counters to do 2D linear bresenham as if the motion along the arc itself was a single axis
// of the line, while the linear "depth" axis was the other.
int32_t linear_counter = -maximum_steps/2;
int32_t arc_counter = -maximum_steps/2;
@ -254,7 +255,9 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
// Execution -----------------------------------------------------------------------------------------------
mode = MC_MODE_ARC;
// Set the direction of the linear or "depth" axis, cause it will never change
direction[axis_linear] = linear_direction;
// Cache some stepper bit-masks to speed up the interpolation code
uint8_t axis_1_bit = st_bit_for_stepper(axis_1);
uint8_t axis_2_bit = st_bit_for_stepper(axis_2);
uint8_t axis_linear_bit = st_bit_for_stepper(axis_linear);
@ -264,18 +267,19 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
while(mode)
{
// reset step bits
// This loop sets the bits in the step_bits variable for each stepper it wants to step in this cycle.
step_bits = 0;
// Do linear interpolation
// The bresenham algorithm chooses when to travel in the depth axis and when to travel along the arc
linear_counter += linear_steps;
if (linear_counter > 0) {
linear_counter -= maximum_steps;
// Move one step in the depth direction:
step_bits |= axis_linear_bit;
}
// Do arc interpolation
arc_counter += arc_steps;
if (arc_counter > 0) {
arc_counter -= maximum_steps;
// Do one step of the arc:
// Determine directions for each axis at this point in the arc
dx = (y!=0) ? signof(y) * angular_direction : -signof(x);
dy = (x!=0) ? -signof(x) * angular_direction : -signof(y);
@ -310,6 +314,7 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
}
}
}
// Tell the steppers to do the stepping
set_stepper_directions(direction);
step_steppers(step_bits);