Re: [CAD_CAM_EDM_DRO] Re: Breakout board or cards - charge pump ?

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