ts-7000
[Top] [All Lists]

[ts-7000] Re: Missing characters in Serial I/P

To:
Subject: [ts-7000] Re: Missing characters in Serial I/P
From: "dokapra" <>
Date: Mon, 23 Feb 2009 17:48:16 -0000
I had similar problems running of SD card. The world 'stops'
sometimes, while kernel is accessing SD card. Poor driver
implementation, no doubt.
I avoided that problem by running of an USB key. USB storage driver is
in much better shape, has better throughput, and is much easier on
processor usage. And does not suffer from blob in kernel.
Then, I had another problem:
I start of an USB key, activate watchdog, and then I try to mount
internal flash (I am using 7260, internal flash is yaffs2 formatted).
Well, this does not work :). Yaffs2 stops everything while parsing
through internal flash, this pause takes longer than 8 seconds, which
is maximum watchdog period... So, by mounting internal flash I reset
CPU. Nice.
Solution for that is not to use watchdog before mounting internal
flash... Not very nice.

--- In  Donal <> wrote:
>
> Thanks guys, I actually implemented a timeout that works perfectly
but this
> isn't the ideal
> solution. I will look into what you've given there Paul.
> 
> Larry,
> Thats interesting alright that you were having similar problems.
> 
> I'll let ye know how I get on.
> 
> Thanks once again.
> 
> Regards,
> Donal
> 
> On Mon, Feb 23, 2009 at 12:53 AM, Larry <> wrote:
> 
> >    I think you are dead on with the flash write theory.
> > I ran into a similar problem on the 7250, and after carefully
eliminating
> > flash
> > writes, I fixed the problem. I'll bet you're missing characters
other than
> > the >,
> > and just are less able to detect that.
> >
> > Donal wrote:
> >
> >  Hi There,
> >
> > I have an application that constantly reads/writes to serial. It
is written
> > in QT, using QExtSerialPort POSIX library.
> > I send a command and the response ends around 250ms later. But
since all
> > commands are different, I don't want to sleep
> > for the worst case (bout 300ms) and then read. Instead I want to keep
> > reading until I hit a '>' character that is always the end of a
response.
> > This works fine, I get my responses in about 230ms.
> >
> > However the problem is, when I am using the app on my TS7390, I
randomly
> > miss the '>' character.
> > This could happen in 1 minute after starting my app, or it could
keep going
> > for say 10 minutes.
> > This results in a loop to infinity waiting for the > character
that was
> > supposed to come but never did.
> >
> > My theory is that since I am running of SD, I may be getting those
random
> > SD writes that hang the system.
> > Would this cause a character to be dropped and not even get into
the serial
> > buffer?
> > I am currently in development stages, so can't move onto NAND just
yet.
> >
> > Alternatively I can implement a timeout feature, but my main
question here
> > is, with a SD write operation, is it possible for
> > the serial in buffer to reject or drop a character.
> >
> > It's a bit of an annoying problem!
> >
> > Oh yeah, memory, CPU usage of this application isn't a problem. A
healty 8%
> > CPU use, with about 14% mem usage.
> >
> > Thanks,
> >
> > Regards,
> > Donal
> >
> > ------------------------------
> >
> > No virus found in this incoming message.
> > Checked by AVG.
> > Version: 7.5.552 / Virus Database: 270.11.2/1965 - Release Date:
2/21/2009 3:36 PM
> >
> >
> >  
> >
>




------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ts-7000/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ts-7000/join
    (Yahoo! ID required)

<*> To change settings via email:
     
    

<*> To unsubscribe from this group, send an email to:
    

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

<Prev in Thread] Current Thread [Next in Thread>
Admin

Disclaimer: Neither Andrew Taylor nor the University of NSW School of Computer and Engineering take any responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU