Re: how to trigger on positive edge only with snl

[Eric Norum <wenorum@lbl.gov>]

Hmm…
Now I read the original article more closely.
Tim's suggestion is a lot better…..

On Mar 21, 2013, at 1:43 PM, Eric Norum <WENorum@lbl.gov> wrote:

> How about the following?
> 
> int bin;   assign bin to "abc:bin";     monitor bin;
> ss ttt {
>    state isZero {
>        when(bin == 1) {
>            printf("Received a trigger!!\n");
>        } state isOne
>    }
>    state isOne {
>        when(bin == 0) { } state isZero
>    }
> }
> On Mar 21, 2013, at 10:04 AM, Tim Mooney <mooney@aps.anl.gov> wrote:
> 
>> Hi Song,
>> 
>> I have not done this myself in SNL, but if I needed to do it, I'd start by looking into the "syncq" and "pvGetQ" commands in the SNL Reference Manual:
>> 
>> http://www-csr.bessy.de/control/SoftDist/sequencer/Reference.html
>> 
>> 
>> Tim
>> 
>> ----- Original Message -----
>>> From: "Song Hu" <Song.Hu@lightsource.ca>
>>> To: tech-talk@aps.anl.gov
>>> Sent: Thursday, March 21, 2013 10:58:28 AM
>>> Subject: how to trigger on positive edge only  with snl
>>> 
>>> Hi,
>>> 
>>> I would like to trigger some actions when a binary PV changes from 0
>>> to 1. No action should be taken when it changes from 1 to 0. I made
>>> some code like:
>>> 
>>> int bin;                  assign bin to "abc:bin";
>>>                                  monitor bin;
>>>                               evflag  binFlag;
>>>                                                                                  sync
>>>                                bin   binFlag;
>>> ss ttt
>>> {
>>> state testState
>>> {
>>>    when(efTestAndClear(binFlag)&&(bin == 1))
>>>    {
>>>          printf("Received a trigger!!\n");
>>>    }state testState
>>> }
>>> }
>>> 
>>> When abc:bin changes from 0 to 1 and then quickly go back to 0, it is
>>> not working every time.
>>> 
>>> What is the appropriate way to implement such positive edge only
>>> trigger?
>>> 
>>> Thanks in advance for your help.
>>> 
>>> Song
>>> 
>>> 
> 
> -- 
> Eric Norum
> wenorum@lbl.gov
> 

-- 
Eric Norum
wenorum@lbl.gov