Hardware step generator idea

I was thinking last night about the timing problems of PC-based step
pulse generator (both frequency and speed resolution at high speed)
and came up with an idea I'd like to bounce off folks.

What about running EMC in servo mode (with encoders) and writing a
driver that takes the number which would be converted to +/-10v by the
STG card and instead uses the magnitude to control a simple pulse
generator and the sign to control the direction bit. (This presumes
EMC can handle velocity mode servo amps). This might even work with
the G320 step-servo drivers (would they then behave like a closed
velocity loop?)

It seems to me that this card could take the form of an 8254
programmable timer (3 channels) running from a suitably fast clock
source and something (74hc373, 8255) to provide bits for the direction
signal. (Software might also need to control the 8254 gate output when
zero speed is commanded)

I know hardware pulse generators are not a new idea, I'm just
attracted by the apparent simplicity of doing it this way, and the
possibility of having an open hardware design to work with EMC.

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT



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--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT