Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

I've got a weird problem I just can't lick, but I'm sure it's something dumb I'm just not thinking of. I have a device hooked to my USB which is emulating a serial port, so I've got /dev/ttyUSB0. I need to send that device a couple characters, and then the device replies with a line. If I open the /dev/ttyUSB0 for update, write my characters, then do a


where DEVICE is my file handle, I get no response from the device. I have made the file handle nonbuffered with select. This read blocks, which is fine, that's what it should do. If, from another session, I then simply echo my characters to >/dev/ttyUSB0, my blocked read gets the response line. If I split the write/read into two different perl scripts and call the read script, then call the write, that works as well. So basically what seems to be happening is that unless I'm reading the port at the time of the write, I miss the response and it's tossed out. Can anyone offer any advice? I've tried Device::SerialPort and really don't like it. It seems to foobar my port to the point where I have to unplug/replug the device (it's not a modem anyway). Thanks Monks.

In reply to stupid serial port issue by mlibhart

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and all is quiet...

    How do I use this? | Other CB clients
    Other Users?
    Others chilling in the Monastery: (10)
    As of 2018-05-22 08:58 GMT
    Find Nodes?
      Voting Booth?