Experimental Physics and
Industrial Control System

Michael Davidsaver <[email protected]> · Thu, 11 Aug 2016 07:32:33 -0400

The short answer is to use the INP or OUT link field to hold address
information.  This can be parsed/processed in the init_record device
support function.  A simple place to start for a VME device is to put a
base address here.

> record(ai, "rec:a") {
>    field(DTYPE, "HW Channel")
>    field(INP  , "@0x20001000")
> ...
> record(ai, "rec:b") {
>    field(DTYPE, "HW Channel")
>    field(INP  , "@0x20002000")

The format of the INP/OUT fields depends on the HW link type.  The
example I give is INST_IO.  Your example 'device()' lines use VME_IO.
You'll run into some problems here if your device using anything wider
than A16.  You should not feel bound to use VME_IO just because it has
VME in its name.

For a longer discussion.

http://mdavidsaver.github.io/epics-doc/epics-ioc.html

On 08/11/2016 06:39 AM, Stefen Paul wrote:
> Hi All,
> 
> I've built device support for ai record for a vme based ADC board.
> 
> I've used the following to add the support:
> 
> device(ai,VME_IO, devAiADCtype1, "HW Channel");
> 
> where devAiADCtype1 is the structure in the device support routine.
> 
> The things are working fine. When I insert an ai record, I get a DTYP as
> 'HW Channel' , I pass on the relevant VME_IO address ant the board gets
> read.
> 
> Now I want to build device support for ai record to support one more
> type of vme based ADC board to be used in the same system.
> 
> How do I do it ? Should I write something like : 
> 
> device(ai,VME_IO, devAiADCtype2, "HW Channel 2");
> 
> or is there another method of doing so ?
> 
> I mean how make multiple device support for a given record type ?
> 
> Please suggest,
> 
> Thanks,
> Stefen
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System