Experimental Physics and
Industrial Control System

"Russ Berg" <[email protected]> · Wed, 6 Nov 2002 09:39:19 -0600

Hi Paul,
Over the past year here at the CLS I have been putting together software and a design for accessing VME through a
PCI fiber link on a PC where the OS is straight Linux. The fiber link boards (PCI: SIS1100, VME:SIS3100)
are made by Struck www.struck.de. Basically the fiber link allows me to map the entire register space
of any VME board in a crate into the user space of the EPICS application. Then once the mapping has been 
completed, all VME board access is via pointer dereferences, its very simple and works well in the EPICS
environment. 

I currently controlling 3 VME crates (about 4 boards each at the moment) with a single PC and one EPICS 
application. When the app starts, crate configuration files are passed as command line arguments, each crate 
is configured by its own cmd file. I have a mix of ADC's, scalars, and digital I/O boards running in each crate. 
I have created 2 generic record types that accomplish 16/32 bit register reads and writes, and I have individual 
dsets for reading FIFO's depending on the ADC. 

Recently I started adding support for interrupt processing, basically if you wanted to process an interrupt
on board x in crate y you write a software driver that has (among the obvious capabilities: open close etc)
the ISR that you want to run when an interrupt occurs on the board. The ISR is then along with the interrupt 
level is registered with the 1100 driver so that when an interrupt occurs on that board, the 1100's ISR will
steer the processing to the ISR you registered. Anyway it works but I have more work to finish on it.

2 cents:
I personally like working on Linux until a limit is found in which I have to find another solution. Using
the gnu tools (gdb especially) makes it easier to work, for me. Cost is great, support is plenty bla bla bla.

Hope this helps,

-Russ

-----Original Message-----
From: TYLER, Paul [mailto:[email protected]]
Sent: Tuesday, November 05, 2002 9:58 PM
To: EPICS (E-mail)
Subject: Advice on VME processor cards for EPICS

Hi.

I've been lurking for a while and reading up on EPICS but think it is time for a question.  We have
been using a home grown control system for our Tandem accelerator that has never really met user's
expectations.  I've been looking at various options to upgrade or redo our control system and
believe EPICS is a good choice for us.  Currently we have VME based hardware with MVME147 processor
cards.  I think it is a lost cause trying to utilise the MVME147s and for the cost of a VxWorks
licences for them, we can upgrade our cards and use a free O.S.

So I'm wondering if anyone has any suggestions on CPU cards for (old) VME crates that might be
suitable for EPICS?  We are trying hard to avoid VxWorks due to the expense.  So that leaves us with
RTEMS or even just running IOCs under Linux.  Our current response times are measured in seconds so
while Linux isn't a "Real Time" OS and has some latency issues, it may well be quite ok.  (Any
comments about that are welcome.)  We don't need huge processing power either.  (We just cope with
the MVME147s.)

So my major question and then a minor one.  Any suggestions on replacement VME processor cards with
Operating System options?  Price is a consideration.  We also have a preference for cards that can
run Linux and RTEMS.  Also is anyone running with Pentium based systems?

If you have any other comments, they would also be welcome.

Thanks in advance.

Paul Tyler

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System