EPICS support for LAN/GPIB gateway HP E2050A

[Benjamin Franksen <franksen@leo.acc.bessy.de>]

To everyone who is interested in a simple and stable GPIB solution under
EPICS:

I rewrote the original GPIB driver (by John Winans) to make it work with
the E2050A. The HP E2050A is a gateway between your LAN and GPIB. LAN
communication is based on a standard by the VMEbus-Consortium called
VXI-11 (freely available) which in turn is based on ONC/RPC (Remote
Procedure Call).

I also made some (very minor) changes to the corresponding device
support library (so it works smoothly together with the new driver). The
process of writing the specific device support modules may be further
simplified by including a generic header file. Essentially only the
parameter table and the parmBlock has to be specified to construct a new
devSup module. Furthermore a special devSup module has been written to
account for the so called 'common commands and queries' specified in
IEEE-488.2. Even a simple common SRQ handler exists, that relays
unsolicited SRQs to an I/O-event scanned eventRecord which, in turn,
reads the event status register of the device (via common query
'*ESR?'). This seems to work with most modern GPIB devices since
nowadays many of them conform at least to the basic 'common commands &
queries'.

The software is still changing but not significantly. A first 'final
release' is about to appear in about a week (I hope!).

	Benjamin Franksen
-- 
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