Re: [CAD_CAM_EDM_DRO] Re: CNC Pulse jitter?

Patrick Mendiuk wrote:

> Jon,
>
> > I'm not sure what you mean, here. There is a 10 MHz crystal oscillator on
> the board.
> > It generates the reference for timing, and can also set the "servo" update
> interval,
> > although EMC doesn't use this at present. If I can figure out how to make
> the
> > RT scheduler schedule a task based on an interrupt other than the interval
> timer
> > on the motherboard, then I can rig this to interrupt the CPU.
>
> So there isn't any support for external clock generators right now?

Again, I am not sure what yu are asking. What sort of clock generator do you
want? Do you mean just for activating a real-time process, or do you mean for
generating step pulses? If you mean step pulses, and EMC, then that is what
my board does.

> I think it might involve more than just the RT scheduler. The stability and
> breaking the 3us boundary would be nice, but I think there would be lots of
> crawling around in the RT source and some intimate evenings with LTT and the
> scope...

3 uS? if you want to schedule a real-time process to run every 3 uS, that is
a tall order, even for a GHz Pentium. If you mean to get step pulse resolution
of 3 uS or better, I am doing 100 nS with my board. it has no processor at
all. The Pentium does the computing, my board generates step pulses at a
rate commanded by the CPU, and keeps track of position by counting the
step pulses (or counting encoders, if so equipped).

Jon