DVX2502 addressing

[saunders@aps.anl.gov (Claude Saunders)]

We have an application here at APS which utilizes up to 4 DVX2502
boards in one VME crate. While thumbing through the driver, I noticed
the register map structure pads out to 128 bytes, while the board base
addresses are selectable at 64 byte boundaries. Is there a particular
reason why the driver was set up this way? We can save some short IO
space by changing it.

Incidentally, I discovered that the sequence ram requires an extra
sample cycle at the end to reset the multiplexer properly (the driver
does this now, it just puzzled me when I saw it). Ie. if you scan 8
channels in a row, the sequence ram MUST be loaded to sample 9 times
before resetting to channel 0. Odd.

  - Claude Saunders