Experimental Physics and
Industrial Control System

I have a very simple VME setup: mvme6100 and SIS3300.

The IOC is built with EPICS R3.14.11 and vxWorks 6.6.  For the SIS3300 I am using gtr R2.3.

I load the IOC, supply a gate to the SIS board and some signals and all works quite well.

Next I insert into the VME crate a VSAM module from BiRa (it’s an A24/D32 no interrupts device, which is basically a 32 channel DVM).  At this point no device driver is built into the IOC software for the VSAM device.

Now, I load the IOC software, without errors.  However, when I enable interrupts in the SIS module, for each trigger (gate) I get the following error:

interrupt:

Clearing VMEbus exception, attrib reg TEMPE_VEAT = 0xc00ccd00

The waveforms from the SIS module look almost as expected, but not quite right.

Next I build into the IOC the device driver for the VSAM module, reload the IOC and still get the same exception when the SIS module is started.

I don’t understand the reason for this. How is it that a simple module (VSAM) in the VME crate can affect the performance of another module (SIS) in the same crate.  I don’t see this behavior with other VME modules in the same crate.

Thanks in advance for any insight into this,

Zen