Re: Aux stuff for ppio

[Ray <rehenry-at-up.net>]

On Thu, 28 Jun 2001, you wrote:
> Hi Folks,
>   I just got emc installed on my system and fired it up. As I'm just
> getting started, I'm not entirely sure which version of the source it
> is (its from the BDI v2.04), but there are checkin comments from mid
> january in some of the files. Unfortunately it doesn't build, but that
> doesn't bother me since I should probably sync to sourceforge if I want
> to do any work.

With the BDI 2.04 release you will need to compile the linux kernel and the
rt kernel before you will have all the header files needed by the EMC
build.  There should soon be a page on linuxcnc.org/bdi on how this can
be done.

>   I was wondering if anyone has started work on using an additional
> parallel port for the minimillio to support some of the additional
> signals that the bridgeportio can use (i.e. estop, spindle on and off,
> individual axis limits and home). The parallel port code will need some
> work to make it support two instances at once, but it shouldn't be too
> difficult.
> 
> thoughts?

Separate limits and home switches for each axis gets to be a real pin hog.
You will quickly run out of inputs to a parport or two.   Perhaps you
could use diodes to create a matrix of 15 switches for 4 input pins.   I
have done this a time or two with Tcl and iosh but have never tried it
with C or real time.

Ray