component sim_spindle "Simulated spindle with index pulse";

pin in float velocity-cmd "Commanded speed";
pin out float position-fb "Feedback position, in revolutions";
pin io bit index-enable "Reset \\fBposition-fb\\fP to 0 at the next full rotation";
param rw float scale = 1.0 
"""factor applied to \\fBvelocity-cmd\\fP.

The result of '\\fBvelocity-cmd\\fP * \\fBscale\\fP' be in revolutions per second.
For example, if \\fBvelocity-cmd\\fP is in revolutions/minute, \\fBscale\\fP should be set to 1/60 or 0.016666667.
""";

license "GPL";

function _;

;;
#include <rtapi_math.h>


FUNCTION(_) {
   double old_position = position_fb;
   double new_position = position_fb + velocity_cmd * fperiod * scale;

   if(index_enable && (floor(old_position) != floor(new_position))) {
       index_enable = false;
       if(velocity_cmd < 0)
           new_position = new_position - ceil(new_position);
       else
           new_position = new_position - floor(new_position);
   }
   position_fb = new_position;
}