Date: Thu, 27 May 1999 09:53:56 +0200 (MET DST) From: Peter Brevik <pb@ludd.luth.se> To: freebsd-hackers@freebsd.org Subject: RS232 status lines, read with TIOCMGET.. [solved] :) Message-ID: <199905270753.JAA00777@father.ludd.luth.se>
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Some of you maybe saw my letter about the (4)tty ioctl "TIOCMGET int *state".
The issue has been solved and the answer is that indeed the sio.c driver only
reads the status line at opening.
However a status line change will trigger a interrupt, and cause the driver to
read status lines once more. Thus functionality achived with minimum cpu load.
Seems the status lines are not sensitive for ground connection. Ie it will not
change bit value between gnd connection and no connection. I guess that was a
bad TTL habit :-)
Maybe this could be used in freebsd handbook or other documentation.. ?
(to help others)
/Peter
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