[Rxtx] Not receiving 0xa characters
weissch at technikum-wien.at
Wed Nov 24 14:29:57 MST 2010
I actually tried to reply about 12 hours ago, but as it seems this message
was for some reasons relayed to the moderators.
I found the error in my code and it was a very simple embarrassing one that
i always read over ... I shouldn't reuse demo code without checking it twice
I'm sorry for bothering you and want to say thanks for all the input when it
was all my fault.
On Wed, Nov 24, 2010 at 7:59 PM, <jfh at greenhousepc.com> wrote:
> On =some= POSIX systems the TERMIOS are reset. On many, they aren't, in
> order to avoid a number of other problems.
> It's always best, because of "lingering termios" problems to build a
> mostly-raw termios by hand. In the case of RXTX, the one problem I saw is
> that the port is initially set to B9600, which means any characters that are
> received immediately are mis-framed. I've seen this in my code where
> gibberish shows up in the initial stream.
> Julie Haugh
> Senior Design Engineer
> greenHouse Computers, LLC // jfh at greenhousepc.com // greenHousePC on
> -------- Original Message --------
> Subject: Re: [Rxtx] Not receiving 0xa characters
> From: Trent Jarvi <tjarvi at qbang.org>
> Date: Wed, November 24, 2010 12:09 pm
> To: "rxtx at qbang.org" <rxtx at qbang.org>
> On POSIX (Mac, Linux, Solaris, ...) systems, RXTX explicitly sets the port
> to 'raw' after opening to avoid those translations/filters. We 'stomp' on
> the port to force it into a predictable configuration.
> term->c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
> term->c_oflag &= ~OPOST;
> term->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
> term->c_cflag &= ~(CSIZE|PARENB);
> term->c_cflag |= CS8;
> On windows, RXTX may not be as robust and could probably use a code review
> by someone familiar with the structs (termios.c).
> I could imagine a driver on windows having unusual defaults RXTX does not
> override causing problems. There are not many drivers out there though.
> I've personally not run into the situation mentioned.
> On Wed, 24 Nov 2010, Kustaa Nyholm wrote:
> > Hi,
> > have look at:
> > http://linux.die.net/man/3/tcsetattr
> > I think (without looking at txrx source code) that the port
> > is opened without correctly setting INLCR,ICRNL and/or IGNCR.
> > But that is Unix/Linux stuff and you are on windows. However,
> > I would suspect there is a similar feature and possibility
> > of a bug in rxtx on Windows too.
> > The obvious workaround is to correct that in the source code
> > if you are able to recompile from source.
> > The other possibility is to try to figure out why the
> > port in question defaults to eating LFs (0x0A).
> > I had a program that had this same bug and hundreds of
> > people used it without a problem until on one Linux machine
> > it failed with similar symptoms to yours, only in my case
> > it was output.
> > So you might be able to somehow configure the port to default to sensible
> > values so that even if rxtx does not set them correctly they
> > would be set correctly by default.
> > Just 2 snt worth.
> > br Kusti
> >> From: Christoph Weiß <weissch at technikum-wien.at>
> >> Reply-To: <rxtx at qbang.org>
> >> Date: Tue, 23 Nov 2010 23:28:15 +0200
> >> To: <rxtx at qbang.org>
> >> Conversation: [Rxtx] Not receiving 0xa characters
> >> Subject: [Rxtx] Not receiving 0xa characters
> >> Dear all,
> >> I am currently trying to work with RxTx on a Windows 7 OS with JDK6
> >> I can connect to a serial port created by a FTDI USB chip and send
> >> data from it. However it seems that I am not able to receive any
> >> with the value 0x0a (LF).
> >> Upon looking into the source code of the serial implementation I found
> >> opening the port happens without the binary flag so I suppose that LF
> >> possibly eaten by the OS. Could this be the problem? Is such a problem
> >> Are there workarounds?
> >> Thanks in advance,
> >> best regards,
> >> Chris
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