Re: [CAD_CAM_EDM_DRO] RE fpga black boxes

ccs@... wrote:

>
> > I am basically just a lurker that has been following this thread. I have
> > NO CNC experience whatsoever. So maybe this comment is totally off the
> > wall, but ...
> >
> > What about using FPGAs as a compromise between dedicated fast but
> > inflexible HW and flexible but slow SW?
>
> Dennis,
>
> That is an excellent idea, and one that several of us have been
> thinking about on and off the list for a while. FPGA's are "field
> programmable gate arrays" which is to say chips that can be configured
> in the field to support various logic functions. That means it should
> be possible to 'download' a new hardware design to ones 'black box'
> from the host PC...

FPGAs are best configured as a dedicated peripheral device,
controlled by a micro. They're good for simple 'machine-like'
repetitive operations, but are clumsy for more complex
programs you'd use in a micro. An ideal combination of
devices would be a micro that reads and interprets serial
data commands from a pc, does a few calculations, then
runs an fpga that is configured to generate multi-phase
sine-wave drive for as many steppers as you want. Because
of the speed and parallel ability (unlike micros, fpgas can do
many things in parallel easily), you could have dozens of
micro-stepping channels in the one chip.