Re: interrupt read data in int32Driver example

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi,

• However, the return value of `caget` did not change. How can I make `asyndevAiInt32A0` generate a read data interrupt to software simulate a hardware interrupt that produces new data?
  

If you open the OPI file for that testEpicsApp program you will see that there is another record that sets the interrupt rate.  That record defaults to 0, so there are no interrupts.  You can set it to a non-zero value either in the OPI screen or with a caput command.

Here I set it to 1.0 seconds using caput:

corvette:~>caput asyndevSetRateInt32 1.0

Old : asyndevSetRateInt32            0

New : asyndevSetRateInt32            1

Now when I run caget on asyndevAiInt32A0 it is indeed changing as you expect:

corvette:~>caget asyndevAiInt32A0

asyndevAiInt32A0               -99.9115

corvette:~>caget asyndevAiInt32A0

asyndevAiInt32A0               -99.8993

corvette:~>caget asyndevAiInt32A0

asyndevAiInt32A0               -99.8962

I can also run camonitor to see it change.

corvette:~>camonitor asyndevAiInt32A0

asyndevAiInt32A0               2023-07-07 07:01:09.423192 -99.8779

asyndevAiInt32A0               2023-07-07 07:01:10.423334 -99.8749

asyndevAiInt32A0               2023-07-07 07:01:11.423444 -99.8718

asyndevAiInt32A0               2023-07-07 07:01:12.423598 -99.8688

asyndevAiInt32A0               2023-07-07 07:01:13.423738 -99.8657

asyndevAiInt32A0               2023-07-07 07:01:14.423891 -99.8627

asyndevAiInt32A0               2023-07-07 07:01:15.424011 -99.8596

asyndevAiInt32A0               2023-07-07 07:01:16.424143 -99.8566

The function in int32Driver that does the interrupt callback is here:

https://github.com/epics-modules/asyn/blob/9e184b6102fba63bc5a536cb26f1c94094b23692/testEpicsApp/src/int32Driver.c#L183

If you plan to write your own driver that does interrupt callbacks I would strongly recommend that you do not use int32Driver.c as an example.  It uses the asyn C interface, which is very verbose and requires a lot of code to do this.  I recommend that you write your driver in C++ and inherit from asynPortDriver.  The code required to do interrupt callbacks is then much simpler.  This is the code that does asynFloat64 callbacks on the "mean value" in the simulation:

https://github.com/epics-modules/asyn/blob/9e184b6102fba63bc5a536cb26f1c94094b23692/testAsynPortDriverApp/src/testAsynPortDriver.cpp#L194

It is just:

        setDoubleParam(P_MeanValue, meanValue);
        callParamCallbacks();

Mark

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of timesir via Tech-talk <tech-talk at aps.anl.gov>
Sent: Friday, July 7, 2023 1:18 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: interrupt read data in int32Driver example

 

Dear community,

I would like to learn about the usage of epics interrupt. I found an example routine called `int32Driver` (asyn/iocBoot/ioctestEpics/st.cmd and asyn/testEpicsApp/src). In the `st.cmd` script, there is a record instance that I want to use to run an interrupt because it has `SCAN=I/O Intr`. Here is the example record instance:

record(ai,"asyndevAiInt32A0") {
    field(SCAN,"I/O Intr")
    field(DTYP,"asynInt32")
    field(INP,"@asyn( int32 , 0 , 1.0) ")
    field(LINR,"LINEAR")
    field(EGUF,"100.0")
    field(EGUL,"-100.0")
    field(PREC,"3")
}

After running `epics` using the above command, I tried to read the data generated by the interrupt using `caget asyndevAiInt32A0`. However, the return value of `caget` did not change. How can I make `asyndevAiInt32A0` generate a read data interrupt to software simulate a hardware interrupt that produces new data?