Re: EMC I/O Config

   From: shymu@...

>Is there a way to config the printer port so I can turn on or off
>spindle and vac motors. I know about adding a second port but would
>rather not. Seems to me I should be able to run 4 axes and still have
>two lines left to control a spindle and vac system.

This is one of those tasks where "seems to me's" don't apply very well. I
proposed a similar sort of thing to the emc list a while back and it turns
out that the sigs are written to the port as one chunk rather than as a
descrete set of pin-directed bits. The trick is to get the I/O output
signals mixed in with the motion signals without causing something that
the NIST folk called a race condition???

You can see simple examples of this with IO_Exercise. If you send a 0
value to the port it will turn off all 8 of the available pins while 255
turns them all on. So each batch of motion signals would need to be added
to the value of the I/O signal. It can be done, Jon Elson has been
working with NIST to do this sort of thing with the boards he is
developing.

Short answer for now, add a $9.00 ISA parport card and use bridgeportio or
if you want to program the card for more specialized tasks use tkio.

HTH

Ray