Async serial communication/threads sharing data

Nick Timkovich prometheus235 at gmail.com
Sun Mar 22 11:13:36 CET 2009


On Mar 21, 9:19 pm, Jean-Paul Calderone <exar... at divmod.com> wrote:
> On Sat, 21 Mar 2009 13:52:21 -0700 (PDT), Nick Timkovich <prometheus... at gmail.com> wrote:
> >I've been working on a program that will talk to an embedded device
> >over the serial port, using some basic binary communications with
> >messages 4-10 bytes long or so.  Most of the nuts and bolts problems
> >I've been able to solve, and have learned a little about the threading
> >library to avoid blocking all action while waiting for responses
> >(which can take 50 ms to 10 s).  Ultimately, this program will test
> >the device on the COM port by sending it messages and collecting
> >responses for 10k-100k cycles; a cycle being:
> > 1. tell it to switch a relay,
> > 2. get it's response from the event,
> > 3. ask it for some measurements,
> > 4. get measurements,
> > 5. repeat.
> >Later I would like to develop a GUI as well, but not a big issue now
> >(another reason to use threads? not sure).
>
> Twisted includes serial port support and will let you integrate with a
> GUI toolkit.  Since Twisted encourages you to write programs which deal
> with things asynchronously in a single thread, if you use it, your
> concerns about data exchange, locking, and timing should be addressed
> as a simple consequence of your overall program structure.
>
> Jean-Paul

I've looked at Twisted a little bit because of some searches on serial
port comm turning up advice for it.  However, there seems to be no/
minimal documentation for the serial portions, like they are some old
relic that nobody uses from this seemingly massive package.  Do you
have any examples or somewhere in particular you could point me?

Thanks for the responses,
Nick



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