laserfreq.comp

component laserfreq "Pulse driver for CO2 Laser";
author "Ben Jackson <ben@ben.com>";
pin in bit enable = 0 "Enable pulse generation";
pin in float velocity = 0 "Velocity of the laser head (e.g. motion.current-vel)";
pin in float pulse-per-unit = 0 "How many pulses per unit distance";
pin out bit pulse "Output firing pulse";
pin out bit continuous "True if current inputs are causing continuous (not pulsed) output";
param rw s32 duration "Duration of each pulse in ns";

function make_pulses nofp "Add to fast thread to make laser pulses";
function update fp "Add to update thread to compute pulse parameters";

variable int updated;
param r s32 interval;
param r s32 accum;
param r s32 pulse_remain;
license "GPL";
;;

FUNCTION(update) {

    if (velocity == 0.0 || pulse_per_unit == 0) {
        updated = 0;
    } else {
        if ( pulse_per_unit < 0.0 ) {
            // duty cycle is just a function of % and duration
            interval = duration * -100.0 / pulse_per_unit;
        } else {
            // velocity * pulse-per-unit gives pulses per second
            // pulse interval is then 1/pps 
            interval = 1000000000.0 / (velocity * pulse_per_unit);
        }
        updated = 1;
    }
}

FUNCTION(make_pulses) {
    if (!enable || !updated) {
        accum = 0;
        pulse_remain = 0;
        pulse = 0;
        continuous = 0;
        return;
    }

    accum += period;
    if (accum > interval) {
        accum -= interval;
        if (accum > interval)
            accum = 0;
        continuous = (pulse_remain > 0);
        pulse_remain = duration;
    }

    if (pulse_remain > 0) {
        pulse = 1;
        pulse_remain -= period;
    } else {
        pulse = 0;
    }
}