RE: Proposed change in asyn - request for comments

[Mark Rivers <rivers@cars.uchicago.edu>]

Hi Michael,

Yes, this would be useable with the interrupt mechanism.

In R4-19 we added support for alarm status in the interrupt callback.  The severity is set to NO_ALARM for pasynUser->auxStatus=asynSuccess and INVALID_ALARM for pasynUser>auxStatus!=asynSuccess. 

Mark



-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Michael Davidsaver
Sent: Wednesday, May 30, 2012 10:44 AM
To: tech-talk@aps.anl.gov
Subject: Re: Proposed change in asyn - request for comments

Hi Mark,

Would this be usable with the asyn "interrupt" mechanism?  Also, have 
you considered adding a field for alarm severity as well?

I would like to be able to push data to records via I/O Intr with a 
valid/invalid flag and a timestamp.

Michael


On 5/28/2012 12:40 PM, Mark Rivers wrote:
> Folks,
>
> Eric Norum and I are proposing a change to asyn to enable standard asyn device support to set record timestamps based on time stamp information from an asyn driver.  The change is backwards compatible.  Here is the proposal:
>
> - Add a timeStamp field to the asynUser structure
>
> - Drivers can optionally set the timestamp field in the asynUser that is passed in interface read() operations and in callbacks to device support for input records.
>
> - asyn device support sets the record timestamps based on pasynUser->timeStamp if the following are both true:
>    - The record TSE field is set to epicsTimeEventDeviceTime (-2)
>    - pasynUser->timeStamp is non-zero
>
> The idea is that the asyn driver can determine the time stamp very close to the time that the I/O operation completed.  The record timestamp can thus be set much closer to the "true" time than if the time is determined with recGblGetTimeStamp later on when the record processes.
>
> Before we commit this change I'd like to hear if this would be useful to others.  I'm particularly interested if this would help the LCLS and other FEL folks who want to timestamp areaDetector and other asyn driver records with the pulse identification.  Are there changes to the proposal that would make it more useful, but still general?
>
> Cheers,
> Mark
>
>