A/B Quadrature from EMC2

By popular demand a simple example of how to modify the stepper_mm sample configuration to output phase-A/phase-B quadrature signals (stepgen type=2).

In core_stepper.hal we specify step type 2, and re-name/wire the stepgen output:

loadrt stepgen step_type=2,2,2

net XA <= stepgen.0.phase-A net XB <= stepgen.0.phase-B net YA <= stepgen.1.phase-A net YB <= stepgen.1.phase-B net ZA <= stepgen.2.phase-A net ZB <= stepgen.2.phase-B

Then in standard_pinout.hal we wire the phases to the parport:

net XA => parport.0.pin-03-out
net XB => parport.0.pin-02-out
net YA => parport.0.pin-05-out
net YB => parport.0.pin-04-out
net ZA => parport.0.pin-07-out
net ZB => parport.0.pin-06-out


Since I have neither a parport nor an oscilloscope at hand right now I'm using some pyvcp LEDs to look at the A/B signals. These are set up with two changes to the INI-file:

[DISPLAY]
PYVCP = phaseleds.xml

and

[HAL]
POSTGUI_HALFILE = pyvcp_phaseleds.hal

The files I'm using are here: phaseleds.tar

Now it is possible to look at the blinking of the LEDs when the machine moves and see the 90-degree out-of-phase square waveform (see also image here).