On Topic: power control - test-drb@ccmp.vtda.org

26 Jun 2001

"Steve Robertson" &lt;steven_j_robertson(a)hotmail.com&gt; wrote:
...
  My ultimate goal is to build an automated Printed
Circuit Board drilling 
 machine using a classic HP 3000 MPE computer running COBOL. I'm not sure if 
 OPTO22 is suitable for that application or not, I'll need to do a lot more 
 experimentation to make that determination. If it's too difficult, I may 
 wind up using a STD BUS computer as a smart controller/interface between the 
 drilling machine and the 3000. 
The sticky bit would be that the 3000's terminal I/O is essentially
one-way-at-a-time: if the terminal device doesn't have a read request
posted, then most data sent from the attached device will be discarded
(the exceptions being break and subsystem break indications).  And 
trying to do anything else with the terminal device will involve 
aborting the read request, doing the something else, and starting a new
read request.

If the OPTO22 protocol can work around this, you're probably OK.
Otherwise, you will probably need to build a front-end processor of
some sort.

If you have questions, feel free to ask, but my COBOL is rustier than
my SPL, and so I will probably present terminal I/O examples in the
latter with heavy [ab]use of MPE intrinsics.

-Frank McConnell