Experimental Physics and
Industrial Control System

[email protected] · Fri, 22 Apr 94 14:51:14 -0500

Hi Carl,

We use the 2502 with the analog mux boards.  The driver works pretty
good.  The only problems have been that the 2502 wants its DMA buffers
in the A24 space.  vxWorks on the 167 is not freindly to this by
default.  You will need the APS mods for the mv167 BSP if you have more
then 4MB ram.

The only trouble I have had with the 2502 is that it did not trigger
the way I wanted it to.  I had to make a special piece of hardware...
but then our application was trying to cascade their muxes with our
own... your mileage will probably be better.

When ordering them make sure you get the proper single- or double-ended
style A/D inputs.  We got some wrong ones once, and they can't just be
jumpered to switch them.

The guys at LANL mentioned to me that when running them, the DMA is
pretty rude in that it holds the bus for long chunks of time.  Our
application runs in short 200kHz bursts so this has not surfaced yet. 
You might want to contact Matt Stettler and ask him about it.  He wrote
the origional driver.

Also check out the driver source code for comments/gripes about
configuring the board.  I recall putting a big block of comments
describing how to select the channels and stuff.  It might provide some
more insight into what kind of environment you will be forced to live
in.

--John

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System