Re: [OctDev] [instrument-control]

[Andrius S. <and...@gm...>]

On Thu, Oct 18, 2012 at 8:38 AM, Juan Pablo Carbajal
<aju...@gm...>wrote:

> On Thu, Oct 18, 2012 at 9:14 AM, Juan Pablo Carbajal
> <aju...@gm...> wrote:
> > On Thu, Oct 18, 2012 at 12:31 AM, Juan Pablo Carbajal
> > <aju...@gm...> wrote:
> >> Hello,
> >>
> >> I am observing weird behaviors and I couldn't pin down at which level
> >> things are going bad. Using instrument-control 0.1.0 from Forge.
> >> Running Ubuntu 12.04 64 bit
> >> Linux 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012
> >> x86_64 x86_64 x86_64 GNU/Linux
> >>
> >> I am using serial communications. I am testing with a physical
> >> loopback (RxD connected to TxD) in this USB2Serial adapter
> >> https://www.sparkfun.com/products/718.
> >>
> >> Problem 1 [Ring bufffer?]:
> >>   s = serial (); # 8-N-1
> >>   srl_baudrate (s,9600);
> >>
> >>   srl_write(s,"hello")
> >>   ans = 5
> >>
> >>   char(srl_read (s,5))
> >>   ans = hello
> >>
> >>   char(srl_read (s,5))
> >>   ans = hello
> >>
> >>   char(srl_read (s,15))
> >>   ans = hellohellohello
> >>
> >>   char(srl_read (s,4))
> >>   ans = hell
> >>
> >>   char(srl_read (s,6))
> >>   ans = ohello
> >>
> >> It looks like as if the buffer is a ring buffer or is really big and
> >> filled with "hello". Maybe flushing the input after reading will solve
> >> the problem? Continued from the example before I got this
> >>
> >> Problem 2 [Hang after flush]:
> >>   srl_flush (s, 1)
> >>
> >>   char(srl_read (s,5)) # This blocks as expected but ...
> >>   srl_read: Interrupting...
> >>   ans =
> >>
> >>   srl_write(s,"hello")
> >>   ans =  5
> >>
> >>   char(srl_read (s,5)) # This also blocks!!!!
> >>   srl_read: Interrupting...
> >>   ans =
> >>
> >> The only way of getting things to work from this point on is to close
> >> the port and open it again.
> >>
> >> Can anybody reproduce this? any suggestions of tests to run to see
> >> whether the problem is at hardware level?
> >>
> >> I also tested with a virtual loopback (command "socat -d -d PTY:
> >> PTY:", this is simpler than the suggestion in the wiki. I can update
> >> that), I do not observe Problem 1, but I can't interrupt the second
> >> call to srl_read
> >>
> >> s = serial("/dev/ptmx", 9600);
> >> srl_write(s,"hello")
> >> ans =  5
> >> char(srl_read (s,5))
> >> ans = hello
> >> octave:5> char(srl_read (s,5))
> >> srl_read: Interrupting...
> >> srl_read: Interrupting...
> >> srl_read: Interrupting...
> >> srl_read: Interrupting...
> >>
> >>
> >> Thanks
> >
> > Testing in Debian Squeeze 2.6.32-5-686 with the same hardware
> > configuration doesn't show Problem 1
> > Note that:
> >
> > - Ubuntu 12.04 uses kernel 3.2.0 and the driver controlling the adapter
> is
> > ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver
> >
> > - Debian Squeeze uses kernel 2.6.32 and
> > ftdi_sio: v1.5.0:USB FTDI Serial Converters Driver
> >
> >
> > In Debian the problem observed is the following (opening the port the
> > same as before)
> >> srl_write(s,uint8(127)); srl_read(s,1)
> > ans = 127
> >> srl_write(s,uint8(128)); srl_read(s,1)
> > ans = 0
> >
> > Should it go up to 255?
>
> Additional update.
>
> Checking the code of srl_write.cc and srl_read.cc I noticed that while
> srl_write writes "unsigned char" srl_read reads "char". Is this
> intentional?
>
> Additionally there is a C style cast in srl_write line 63. I assume it
> should be a static cast and therefore it should be
>
> buf[i] = static_cast<unsigned char>(data(i));
>
> Or is there a reason why to do it the C way?
>
>
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Thanks for noting this.

Indeed you are right, fix pushed to the SVN.