On 01:38 pm, hend...@microcorp.co.za wrote:
On Friday 14 August 2009 12:54:32 Diez B. Roggisch wrote:
How about using pyserial? With that, I never had any problems
accessing
the the serial ports, and AFAIK no duplex-problems as well. And I
seriously doubt that these are a python-related problem - python only
has a very thin, direct layer above the posix-calls, and doesn't do
anything that would explain your observed behavior. The GIL is not the
issue here either - it won't interfer with blocking IO.
I will have a look at pyserial - have never used it before.
I agree that it is probably not a Python issue, and that the GIL is
irelevant - I was hoping that someone had already travelled the road
and
could give me a signpost.
In the meantime I have had another idea which I have also not tried
yet,
namely to do independent opens for reading and writing, to give me two
file
instances instead of one, and to try with that. I have no idea if it
would
make any difference, or even work at all.
My normal stuff works, but I do not like it as it is essentially busy
looping
with short sleeps in between. In the eBox, it uses most of the
processor just
to move a few bytes of I/O in and out between the serial port and the
TCP/IP,
and struggles to do that better than five times a second, while the
message
time on the 115200 baud port is only about 2 milliseconds.
One strategy you might employ to get rid of the busy looping is to use
Twisted and its serial port support. This also addresses the full-
duplex issue you've raised.
Jean-Paul
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