Re: Serial port, DTR & CTS

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Thu, 11 Nov 1999 09:50:04 +0100 (MET)

Linux Lists (AKA Ivan?) wrote:
>
> On Wed, 10 Nov 1999, David Monniaux wrote:
> >
> > Can I work around this? Is there any way to tell the kernel not to touch
> > the RTS and DTR lines, except when explicitely requested by ioctl's?
>
> For 2.0.x kernels, it seems that there is no way to do it. For 2.2.x (and
> probably for 2.3.x as well, although I didn't check that), it seems that
> opening the port with baud rate 0 (zero) will do the job.

1) How do I open a port with a baud rate of 0? Indeed I have a few
serial ports that don't do exactly what they were designed to do, so I
also don't like the RTS signal doing funky stuff when I open the port
just to toggle the DTR signal...

(Did you know you can tie a led directly between a handshake signal
and ground? No extra components required! (Don't do this at home, this
violates ALL specs))

2) This sounds like an oversight in the driver. I mean I don't know
about these semantics, and I write serial drivers....

Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
 "I didn't say it was your fault. I said I was going to blame it on you."


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