RE: VXI shared memory transfer

["Jeff Hill" <johill@lanl.gov>]

John,

The VXI libraries available with EPICS only support the core message
base protocols. That was all that was supported by the hardware
available at the time. It would be great if someone volunteered to add
additional code for the higher performance message based protocols. The
VXI support libraries have not changed much in the last 10 years and
could certainly use some upgrades. In particular, a plug compatible
interface for VXI slot zero controllers is also needed.

Quite some time ago I wrote a driver for a message base VXI waveform
generator for the SSC. I vaguely recall that the waveform was
transferred through shared memory, but this was a backdoor that was
specific to this particular device and therefore probably not useful in
your context.

Jeff

> -----Original Message-----
> From: John Faucett [mailto:faucett@lanl.gov]
> Sent: Friday, January 25, 2002 4:56 PM
> To: tech-talk@aps.anl.gov
> Subject: VXI shared memory transfer
> 
> I am writing device support for a message-based VXI module that
> supports two modes of data transfer:
> 
> (1) Via a message, specifically through the SCPI "TRACE #" command.
> This is too slow -- 1000 words takes 30 seconds.
> 
> (2) Via shared memory, using the SCPI "SMEM" command.  The
> documentation shows an example using the VISA viMoveAsync routine,
> but I believe there is no VISA library for EPICS.
> 
> Can anyone give me pointers on writing a routine using shared memory
> transfer?  The VXI slot-0 controller is a hkbaja60 module.