Device driver for NOAO instrument

[rwolff@noao.edu (Richard Wolff)]

Looking for suggestions for a suitable existing device driver, or a
place to start, as we convert NOAO instruments to work with EPICS:

In some existing NOAO instruments, we have a Sun talking to a transputer
based board in an external VME crate through a hardware link that maps
a portion of the Sun memory space into VME memory.  When we move to
EPICS, we need to use some kind of driver to emulate the existing
system (assuming [initially] minimal rewrite of the non-sun side);
we'll retain the VME/transputer board and replace the VME/Sun link with
a 68040/EPICS system.  So what we need is an EPICS device (driver) that
does I/O to the VME backplane.

Part of the cleverness of the existing software involves making some
of the shared memory appear as a serial port, so that the Sun
talks to a transputer link via a standard /dev/xxxx Unix serial
line.  We need to retain this initially.

My initial notion is that almost any device driver would work since
each of them necessarily talks to some set of addresses on the VME
backplane, and we would just rip out the parts that talk to hardware
registers or do elaborate initialization, etc. since we just want to
read and write blocks of memory.  And I also thought that we could take
any rs-232 driver, and again replace the hardware specific stuff with
reference to the couple of memory addresses that appear, externally, to
be the Rx and Tx parts of serial port 0 of the onboard transputer.

But are there better starting points that someone can recommend?
Is there, perhaps, a simple memory driver.

Thanks,

Richard Wolff