Re: Breakout board or cards - charge pump ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Stephen Wille Padnos
<spadnos@s...> wrote:

> turbulatordude wrote:
>
> >As I understand, Mach2 is the only software that uses the feature.
> >
> >It outputs a frequency signal on one pin.
> >
> >with a comparitor, resistor and cap, you can generate a simple

filter

> >that will be charged with the signal and the comparitor can see

the

> >elevated voltage, then turn on a curcuit that would allow the rest

of

> >the board to be live.
> >
> >It is more complicated than that. I would put a PIC on the input

and

> >do it in software, or an op-amp to boost the signal, filter it and
> >act as both the comparitor and output filter (to prevent noise
> >problems)
> >
> >
> Yes - it is more complicated. If the software crashes and leaves

the

> port bit in the high state (or the POST routines happen to do

that),

> then everything looks fine to the comparator. This can easily be

solved

> with a microcontroller, or even easier with a one-shot in the

circuit.

>
> - Steve

Correct, pulse detection needs to ignore the high and the low.

A Charge Pump takes the frequency and by means of charging a
capacitor, generates a higher voltage from the signal voltage (or
something similar)

either way, the signal needs to detect in the pulse is present and
ignore the port being high or low in a steady state.

And a PIC would offer a means of detecting a pulse and responding
accordingly.

It is interesting to see how much of the posts are geard toward
buying things and less of the making things we had some years ago.

Dave