Experimental Physics and
Industrial Control System

Heinrich du Toit <[email protected]> · Fri, 29 Jun 2007 14:37:25 +0200

Hi

I've created an asyn driver that provides a asynInt32 multi_device
interface. Actually the addr is simply different "registers" on the same
device.
Everything works fine - well mostly.
The registers are multi-directional in the driver.
ie. you can write them and you can read them. - Interrupts also works
Offcourse some registers are for reading and other for writing.

Now on one such register for writing I've put a longout record.
As this register will configure the device I want to put in a default
value in the .db file.
so I added the DOL field to the longout register. (this will set the
default VAL of the record and it does)
But when the system initializes the thing goes and READ this register
using the driver. This not only overwrites the default value. It also
gives some garbage as the device can be in unknown state.

I've made a workaround using DrvUser Interface and passing a startup
value that way - but this just doesn't seem like a good solution.
Why does a longout record call the drivers READ command at startup?
Doesn't make sense 2 me.

-Heinrich

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System