normally, there is a latency of ~5-10msec before characters are processed. This can be reduced with setserial, with the low_latency parameter.
The maximum of 250msec that you mentioned seems very slow, however. Have you made sure that your serial driver uses interrupts, otherwise it may fall back to polling. -Erwin Am Donnerstag, den 28.05.2009, 09:27 +0200 schrieb Emmanuel Viollet: > Hi. > > I'm running uclinux 2.6.24.2-uc0 on an Olimex LPC2468 evaluation board > and have an issue with serial ports. > > I'm using the standard Linux serial functions (open(), write(), etc.), > and have discovered (after analysis with an oscilloscope) that the delay > between the write() function and the actual ouput on the serial port > varies between 20 and 250 ms. > I find this delay quite long. Is there anything I can do to force the > serial output as soon as I've put the data in the output buffer? > > Also, the tcdrain() function returns approx. 20ms AFTER the data has > finished being sent by the UART. Is there any way to reduce this delay? > > In advance, thanks. > > _______________________________________________ > uClinux-dev mailing list > [email protected] > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > This message was resent by [email protected] > To unsubscribe see: > http://mailman.uclinux.org/mailman/options/uclinux-dev -- Dipl.-Ing. Erwin Authried Softwareentwicklung und Systemdesign _______________________________________________ uClinux-dev mailing list [email protected] http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by [email protected] To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
