Re: Transition Board

[mooney@oxygen.aps1.anl.gov (Tim Mooney)]

Guy, re...

> Maybe we could provide buffering and eliminate configuration switches by
> connecting the P2 lines to the inputs of a PAL and running the outputs of the
> PAL to the front panel connectors.   Then we could define a few standard PAL
> programs to implement all the permutations we actually want, rather than
> attempting to provide all conceivable permutations.
> 
> We could provide pads for limit switch filters on each of the front panel
> connector lines and then only install caps on the ones which were to be used.

I was thinking more in terms of separate transition connectors for

1 VME8 to StepPak
2 VME4-4s to StepPak

and I'd like something as simple as is consistent with needs to buffer
signals and to support user modifications such as those Mark Rivers
mentioned (e.g., route a buffered copy of a user-selected signal to a
BNC connector).  Since OMS step/dir outputs are open-collector by
default, we could accomplish this routing simply with a jumper on a
16-pin DIP header--without fear that user modifications could damage
anything.  A prototyping area would facilitate kludging the transition
boards to support other drivers that aren't widely enough used to
justify development of their own transition board.  There's no reason
not to preload that prototyping area with the two chips that would be
required to change step/direction to step/step.

Tim