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Subject: Re: Failure to read serial port after ~5000 asynch reads
Date: Fri, 3 Oct 2008 13:47:22 -0400
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"Scott Burnside" <no@spam.com> wrote in message 
news:gc3a48$bjs$1@fred.mathworks.com...
> "Scott Burnside" <no@spam.com> wrote in message 
> <gc1479$or1$1@fred.mathworks.com>...
>> "Trent Jarvi" <tjarvi?hox
.?%wrote in message 
>> <gc0tco$6v3$1@fred.mathworks.com>...
>> >
>> > "Scott Burnside" <no@spam.com> wrote in message
>> > news:gbub92$9sr$1@fred.mathworks.com...
>> > > Running R2007a on WinXP with Instrument Control Toolbox 2.4.2 I am
>> > > encountering serial port read failures after approx. 5000 read 
>> > > operations
>> > > connected to a TrueTime XL-DC GPS Time and Frequency Reciever.
>> > >
>> > > I've used continuous asynchronous, manual asynchronous (with 
>> > > readasync).
>> > > I've tried flow control. All methods manifest the same problem, there 
>> > > is
>> > > no output after about 5000 reads. It looks like Matlab's interface to 
>> > > the
>> > > UART driver is locking up. Serialbreak doesn't work.
>> > >
>> > > Nothing short of closing MATLAB and starting a new instance will 
>> > > clear
>> > > this up.
>> > >
>> > > Is this a known problem with 2007a? I find hints of this in the 
>> > > support
>> > > literature but I would like to be more certain before I spend the 
>> > > money to
>> > > upgrade.
>> > >
>> >
>> > Hi Scott
>> >
>> > AFIAK, this is not a known problem in 2007a.  It may be a manifestation 
>> > of
>> > something else.   Do you have minimal example code that can reproduced 
>> > the
>> > problem?
>> >
>>
>> Trent thanks for replying. I've gotten a trial version of 2008a and am 
>> testing with that overnight. Right away it started out by droping every 
>> other read operation so its clear I had to much going on in the loop 
>> between reads and the 2007a serial interface was trying to cope 
>> unsucsessfully. The 2008a serial interface seems more robust but I won't 
>> know for sure until I see this run overnight.
>>
>> If I continue to have problems I will post some representative code. 
>> Thanks again for your help.
>>
>> Scott
>
> Ok this is worked for about 10-hours total now using R2008a. The thing is 
> that I'm not sure if it 2008a that fixed that problem or the fact that I 
> trimmed alot of the bloated code in the read loop. I guess I should go 
> back and test against R2007a again just to be sure. I'll post back with 
> that result.
>
> The program reads Agilent N9020a Spectrum Analyzer marker peak search 
> frequency and amplitutde at 10 samples-per-second over Ethernet. The data 
> are time tagged with UTC 1-pulse-per-second time stamps taken over the 
> serial port from a TruTime XL-DC GPS/Rubidium Time Standard. The 
> intersecond tics are derived from the internal high resolution counter. 
> I'm using a mex file for that (hat.mexw32 from the FEX). The resulting 
> timestamps are accurate to within 2 ms of absolute UTC time. I'll likely 
> post this code to the FEX after some refinement and much more testing.
>

Hi Scott,

It may be changes we put in for the GPIB and VISA and or TCPIP interfaces 
that also improved Serial.  I didn't find a bug report for your exact 
problem.

Neat application.  I'd be interested in seeing it when you are ready. 
Perhaps the upcomming LXI class B compliant machines (including Agilent SAs) 
would be useful in this application.