Ok, seeing it is Christmas, here is gearbox2 component (Note the name change) with enhancements suggested by Andy.
and also a new output pin "gearbox2.speedratio" you can use to set the pid FF0 as per Andy's suggestions.
Code:
component gearbox2 "LinuxCNC HAL component for Techno's gearbox";
author "Rod Webster";
pin in bit input_a "input a";
pin in bit input_b "input b";
pin in bit input_c "input c";
pin in bit input_d "input d";
pin in bit input_e "input e";
pin in bit gear_shift "gear shift, true if high";
pin in bit higear "true if in high gear";
pin out float speed "speed in RPM";
pin out float speedratio "max RPM for machine divided by maximum RPM for gear";
param rw float maxrpm "maximum RPM for machine";
function _;
license "GPL";
;;
#include <rtapi_math.h>
FUNCTION(_) {
static double speedarray[4][5] = {
{2500.0, 1500.0, 900.0, 540.0, 325.0},
{1500.0, 900.0, 540.0, 325.0, 195.0},
{1250.0, 750.0, 450.0, 270.0, 160.0},
{ 750.0, 450.0, 270.0, 160.0, 100.0}
};
int idx;
idx = (higear) ? 0:1 + (gear_shift) ? 0:2;
if(input_a)
speed = speedarray[idx][0];
if(input_b)
speed = speedarray[idx][1];
if(input_c)
speed = speedarray[idx][2];
if(input_d)
speed = speedarray[idx][3];
if(input_e)
speed = speedarray[idx][4];
speedratio = maxrpm/speed;
}
