Messages in this thread | | | Date | Thu, 22 Mar 2001 13:17:42 -0700 (MST) | From | Trent Jarvi <> | Subject | Re: Serial port latency |
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On Thu, 22 Mar 2001, Geir Thomassen wrote:
> Trent Jarvi wrote: > > > > Hi, > > > > I'm not on the kernel list. I just ran across your email while looking at the > > weekly archive. > > > > I think you want to enable software flow control. > > > > tcgetattr( fd, &ttyset ); > > ttyset.c_iflag |= IXOFF; > > tcsetattr( fd, TCSANOW, &ttyset ); > > > > Just tested it, it didn't change anything. The response from the controller > can contain ^S/^Q, so it would be a bad idea anyway .... > > > Someone reported that the Java CommAPI driver at http://www.rxtx.org got > > 150-200ms latency with (9600,N,8,1,XON/XOFF). Beyond that you may have to > > look at something like the realtime support. I guess 2 ms is normal on > > win98. > > Win98 is the problem I am trying to solve with my program ... > > > Since you have the scope hooked up you may look at hardware flow control too. > > > > tcgetattr( fd, &ttyset ); > > ttyset.c_cflag |= HARDWARE_FLOW_CONTROL; > > tcsetattr( fd, TCSANOW, &ttyset ); > > Do you mean CRTSCTS ? HARDWARE_FLOW_CONTROL is not defined in my header files. > I use CLOCAL, which should make the driver ignore modem control lines. >
Ya.. My bad. I use that to support multiple platforms
#ifdef CRTSCTS #define HARDWARE_FLOW_CONTROL CRTSCTS #else
Do you happen to have shared interupts enabled in the kernel?
> > Let me know if you find anything out. I'm the maintainer of rxtx and would > > be interested in documenting this for others. > > sure ... > > > -- > > Trent Jarvi > > TrentJarvi@yahoo.com > > Thanks anyway > > Geir >
-- Trent Jarvi TrentJarvi@yahoo.com
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