Experimental Physics and
Industrial Control System

[email protected] (Tim Mooney) · Thu, 22 Aug 1996 11:17:28 -0500

Ric, re...

> I'm writing driver, device and record support for a set of custom VXI 
> modules.  These modules have several functions, but share a number of 
> things like a subset of the VXI A16 registers, interrupt handling, etc.  
> Because of the desire to keep things self consistent and efficient, I 
> created one record type per module type.  This makes for fairly messy
> device support, as there is a lot of checking going on to figure out 
> which record field changed that caused the record to process.  Does
> anyone have a cleaner way to deal with this?  Perhaps something to the
> effect of using RSET->special to figure out which field caused
> processing
> and using that information (somehow) to tell RSET->process which
> DSET->process
> function to call?  Perhaps call DSET->process in RSET->special directly?

I've used special() just as you've described to simplify record-support
code.  Give your record a field you can use as a bitmap, e.g.

	"Monitor Mask" MMAP SPC_NOMOD ASL1 DBF_ULONG NO	3 ...

In special(), set the bit associated with the field that has changed:
	.
	.
	#define	M_MRES		0x00000080
	#define	M_ERES		0x00000100
	.
	.
	static long special(struct dbAddr *paddr, int after)
	.
	.
	if (paddr->pfield == (void *)&pmr->mres) pmr->mmap |= M_MRES;

>   Second, the records properly handle Is and Os from/to the modules when
> they are marked scan passive.  However, the modules can also raise 
> interrupts when they detect faults.  I would like to get that
> information
> into record fields for display on an operator screen.  Setting up for
> the I/O Event scan mode appears to lock out processing due to
> modification of record fields from operator screens.

One possibility is to use an EVENT record with SCAN = "I/O Intr" to
detect the interrupt and forward link to the scan-passive record.

Tim

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System