From: Leslie Viljoen <leslieviljoen@...>
Date: 2006-06-10T06:51:50+09:00
Subject: Re: serial port

On 6/8/06, Joakim Oman <joakim@verse.se> wrote:
> Hello
>
> I have been trying to come up with a simple way of utilizing the COM1
> port on my Windows XP Machine. The result is at the end of this entry
> (sorry for the linebreaks)
>
> This program requires that the tx and the rx ports on the COM-port are
> connected. The program is just talking to itself.
>
> The second thread in the program listed below is the listner and if I
> remove the sleep function the whole things goes havoc. What I would like
> is if someone could tell me why or even better, come up with a really
> nice and functional serial communication class that works with win32
>
> /Joakim
> -----------------------------------------------------------
> class Serial<File
>
>         def
> initialize(device="COM1",modeString="r+",baud="9600",parity="n",data="8",stop='1',retryy="n")
>                         @device =       device
>                         @baud   =       baud
>                         @parity =       parity
>                         @data   =       data
>                         @stop   =       stop
>                         @retryy =       retryy
>                         modestr = "mode "+@device+" baud="+@baud+" parity="+@parity+"
> data="+@data+" stop="+@stop+" retry="+@retryy
>                         system(modestr)
>                         super(device,modeString)
>         end #initialize
>
> end
>
> test1=Serial.new("COM1:", "r+","14400")
>
> t1=Thread.new{
> loop{
>                 test1.write("abcdefghijklmnopdqrstuvxyzABCDEFGHIJKLMNOPQRSTUVXYZ")
>                 sleep(1)
>         }
> }
> t2=Thread.new{
> loop{
>                 res=test1.read
>                 p res if(res.length>1)
>                 sleep(0.015)
>          }
> }
>
> t1.join
> t2.join
>

By havoc I assume you get garbage back?
I'd suggest synchronising the threads and seeing what happens. It may
be a thread safety issue with reading and writing the same "file" at
the same time.

Since you probably won't have that problem when actually communicating
with other devices, your class may already be functional.

Les