RE: asyn Driver questions

["Szalata, Zenon M." <zms@slac.stanford.edu>]

Thanks Eric,
I did try this and it made no difference.

I have a fix.

In echoDriver.c, in the echoDriverInit, there is a code fragment:

    if(multiDevice) {
        status = pasynOctetBase->initialize(portName,&pechoPvt->octet,0,0,0);
    } else {
        status = pasynOctetBase->initialize(portName,&pechoPvt->octet,1,1,0);
    }

I changed this to 

    if(multiDevice) {
        status = pasynOctetBase->initialize(portName,&pechoPvt->octet,0,0,0);
    } else {
        status = pasynOctetBase->initialize(portName,&pechoPvt->octet,0,0,0);
    }

and now my code works.  Is this the correct fix?  I really don't know.  The problem is that I took echoDriver.c, made number of modifications, most of them seemed to be working and this one little detail was proper for echoDriver.c but not for what I am attempting.
Anyway, perhaps that is it.  Now I can look at the example you sent me at my leasure.

Zen

-----Original Message-----
From: Eric Norum [mailto:eric@norum.ca] 
Sent: Wednesday, April 21, 2010 12:51 PM
To: Szalata, Zenon M.
Cc: Mark Rivers; TECHTALK Tech-Talk
Subject: Re: asyn Driver questions

When you configure the port just ask that the EOS processing be omitted:
	drvAsynIPPortConfigure("HMx01","134.79.64.51:9999 UDP",0,0,1)



On Apr 21, 2010, at 12:40 PM, Szalata, Zenon M. wrote:

> Hi Mark,
> I looked at asynPortDriver and decided that I should look at it in some near future.  For the time being, I have gone ahead trying to understand how various asyn components work.  To this end I am staying with my attempt at a low level asyn driver, which I call drvMarx.c and which is based on Marty Kramer's echoDriver.c.
> I now understand what is happening but as yet don't know what is the right solution.
> I am now using asyn4.13.
> When I process the epics records, the following action is triggered:
> 1. drvMarx:mxWrite() is called and it sends the string to my python "echo" program.
> 2. The python program, converts the string to upper case and sends it back.
> 3. drvMarx:mxRead() routine is called and it calls asynOctetSyncIO:readOnce().
> 4. asynOctetSyncIO:readOnce() calls asynOctetSyncIO:readIt(),
> 5. asynOctetSyncIO:readIt() calls pioPvt->pasynOctet->read().  This turns out to be:
> 6. asynInterposeEos:readIt().  As I see it, this is where trouble is.  In this routine,
>   peosPvt->processEosIn is 1, therefore the execution goes into the for(;;) loop.
>   In this loop, peosPvt->poctet->read() is called twice.  The first time it succeeds
>   but the second time it times out (not surprising since there is no more data to be
>   read from the port).  In the for(;;) loop, there is some fancy handling of EOM stuff.
>   I don't understand that.
> 
> I tried the following in my st.cmd file:
> asynInterposeEosConfig( "HM01",0,0,0)
> This did not affect the value of peosPvt->processEosIn, it is still 1.
> 
> What is the correct solution to this?
> It is clear to me that the read should be done only once.  It seems to me that in my case processEosIn should be 0 and that would solve the problem that the read (recv) from the port is done a second time, which fails with time out.  Or should the EOM parameters be configured somehow, such that the execution goes only once through the for(;;) loop?
> 
> I really need some straightening out on this.
> 
> Thanks in advance,
> Zen
> 
> -----Original Message-----
> From: Mark Rivers [mailto:rivers@cars.uchicago.edu] 
> Sent: Saturday, April 17, 2010 11:18 AM
> To: Szalata, Zenon M.; TECHTALK Tech-Talk
> Subject: RE: asyn Driver questions
> 
> Hi Zen,
> 
> It looks like you must be using a pretty old version of asyn, R4-9 (October 2007) or earlier, because the asynOctetSyncIO->readRawOnce function was removed in R4-10.  The release notes for R4-10 do say:
> 
> ***
> 
> 
> drvAsynIPPort
> 
> 
> Cleaned up timeout handling.
> 
> ***
> 
> I am not sure if going to a more recent release will fix your problems or not, but if possible I would try that first.
> 
> What type of device-specific asyn driver are you trying to write?  The only documents are the ones in asyn.  I have recently added a new C++ base class, asynPortDriver, that makes writing a device-specific driver very easy, particularly for complex devices with lots of parameters.  I think it is well documented, and there is a well-commented example in asyn/testAsynPortDriver.
> 
> Mark
> 
> 
> ________________________________
> 
> From: tech-talk-bounces@aps.anl.gov on behalf of Szalata, Zenon M.
> Sent: Sat 4/17/2010 12:38 PM
> To: TECHTALK Tech-Talk
> Subject: asyn Driver questions
> 
> 
> 
> I am trying to learn how to write a driver module which is based on echoDriver.c written by Marty Kramer, which I renamed to drvMarx.c.  I have a soft IOC, which includes the drvMarx.c module and which is intended to communicate with some Ethernet device.  The network protocol is UDP.  Presently the Ethernet device is simulated with a simple Python script which receives text message, converts the text to all upper case and sends this back.  The script is working fine.
> 
> In drvMarx.c I am calling asynOctetSyncIO->readRawOnce, which fails with a timeout.  Here is the code fragment from the read routine in drvMarx.c:
> 
> printf( "\n");
> printf( "mxRead:before:readRawOnce: data=%s,nbts=%d,oemReason=0x%x\n",
> data,*nbytesTransfered,*eomReason);
> printf( "\n");
> 
>  status=pasynOctetSyncIO->readRawOnce( pmxPvt->udpPort,0,data,maxchars,
>        5,nbytesTransfered,eomReason,"");
> printf( "\n");
> printf( "mxRead:after:readRawOnce: data=%s,nbts=%d,oemReason=0x%x\n",
> data,*nbytesTransfered,*eomReason);
> printf( "\n");
> 
> This is what I have in my db file:
> 
> record( stringout, "$(P):SO:SEND:IT"){
>  field( DESC, "Send msg")
>  field( FLNK, "$(P):SI:READ:IT")
> }
> record( stringin, "$(P):SI:READ:IT"){
>  field( DESC, "Read msg")
>  field( DTYP, "asynOctetWriteRead")
>  field( INP,  "@asyn($(P),0,1) $(P):SO:SEND:IT")
> }
> 
> When I put the string Hello in the stringout record, this is what gets output:
> 
> epics> 2010/04/17 10:02:25.337 HM01 queueRequest synchronous
> 2010/04/17 10:02:25.337 HM01 mxDriver:write addr 0
> 2010/04/17 10:02:25.337 HM01 lockPort autoConnectOK 1
> 2010/04/17 10:02:25.337 HM01 flush
> drvMarx:mxFlush
> 2010/04/17 10:02:25.337 HM01 mxDriver:flush addr 0
> 2010/04/17 10:02:25.337 HM01 mxFlush
> 2010/04/17 10:02:25.337 asynOctetSyncIO flush
> 2010/04/17 10:02:25.337 HM01 unlockPort
> 2010/04/17 10:02:25.337 HM01 write
> Hello
> 2010/04/17 10:02:25.337 HM01:SI:READ:IT devAsynOctet: writeIt
> Hello
> 2010/04/17 10:02:25.337 HM01 mxDriver:read addr 0
> 
> mxRead:before:readRawOnce: data=,nbts=0,oemReason=0x0
> 
> 2010/04/17 10:02:30.338 asynOctetSyncIO readRaw failed 134.79.64.51:9999 UDP timeout: Resource temporarily unavailable
> 
> mxRead:after:readRawOnce: data=HELLO,nbts=5,oemReason=0x0
> 
> 2010/04/17 10:02:30.338 mxRead nbytesTransfered 5
> 2010/04/17 10:02:30.338 HM01:SI:READ:IT devAsynOctet: readIt failed
> 
> Note that some of the output is generated by printf statements I put in the code.
> Also note that readRawOnce returns the correct value, which means that it received the data from the python script and yet it failed.
> Here is the st.cmd file:
> 
> #!../../bin/linux-x86/marx
> 
> < envPaths
> 
> cd ${TOP}
> 
> dbLoadDatabase("dbd/marx.dbd")
> marx_registerRecordDeviceDriver(pdbbase)
> 
> drvAsynIPPortConfigure("HMx01","134.79.64.51:9999 UDP",0,0,0)
> 
> mxDriverInit("HM01",0,0,0,"HMx01")
> 
> dbLoadRecords("db/marx.db","P=HM01")
> 
> cd ${TOP}/iocBoot/${IOC}
> 
> asynSetTraceMask("HM01",0,0xff)
> asynSetTraceIOMask("HM01",0,0x2)
> 
> iocInit()
> 
> ## Start any sequence programs
> #seq sncExample,"user=whitegrHost"
> 
> The big question is why is readRawOnce timing out?
> 
> Is there a document describing how to write a device specific asyn device driver?  I see examples in the asyn distribution, like the echoDriver.c, but I find it very difficult to decipher those examples.  Therefore I am stumbling around, much of the time not knowing what is the correct approach.
> 
> Thanks in advance,
> Zen
> 
> 
> 
> 
> 

-- 
Eric Norum
eric@norum.ca