On Apr 8, 11:17 am, Grant Edwards <inva...@invalid.invalid> wrote: > On 2010-04-07, Max Kotasek <mawr...@gmail.com> wrote: > > > I'm trying to figure out how to parse the responses fromfcntl.ioctl() > > calls that modify the serial lines in a way that asserts that the line > > is now changed. > > Two comments: > > 1) None of the Linux serial drivers I've worked on return line states > except when you call TIOCMGET. > > 2) If the TIOCMBI[S|C] call returned a 'success' value, then the > line was set to what you requested. > > If you want to read back the state that you just wrote, you can call > TIOCMGET, but for the "output" pins it's always going to return the > last value that was written. > > > For example I may want to drop RTS explicitly, and > > assert that the line has been dropped before returning. > > Call TIOCMSET. If it doesn't return an error, then you're done. > > > Here is a brief snippet of code that I've been using to do that, but > > not sure what to do with the returned response: > > What returned response? > > The only thing that is returned by TIOCMBIS/TIOCMBIC is a status value > of 0 for success and <0 for failure. IIRC, that value is checked by > Python'sfcntl.ioctl wrapper and it will raise an exception on > failure. > > > Is someone familiar with manipulating serial signals like this in > > python? > > Yes. > > > Am I even taking the right approach by using thefcntl.ioctl call? > > Yes. When you set/clear RTS or DTR do they not go up/down? > > Even if you can't use pyserial, it's a good source for example code. > > -- > Grant Edwards grant.b.edwards Yow! TONY RANDALL! Is YOUR > at life a PATIO of FUN?? > gmail.com
I appreciate the feedback. I'm working in an environment with a lot of changing factors, it's nice to have a piece not act unexpectedly. Max -- http://mail.python.org/mailman/listinfo/python-list
