Re: should RTS init in serial core be tied to CRTSCTS

From: Krzysztof Halasa
Date: Thu Mar 08 2007 - 11:51:51 EST


Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@xxxxxxx> writes:

> Unless you want two machines to monitor each other via serial console and
> each of them has only one serial port. It's not perfect, but it works well
> enough despite all claims to the contrary.

Sure, if you don't need "input" (only "console logger" function and
not "initial input/output terminal"). It has nothing to do with the
RTS "problem", though.

BTW: reasonably working, standard-compliant USB-RS232 converters
cost $15 or so. Unfortunately not that all machines have USB ports.

I agree with Russell - mixing kernel console and application's
port is asking for trouble.

OTOH I wonder what does the device in question require WRT the
serial port and WRT RTS line in particular.
I know there are some half-duplex converters which drive RTS only
while sending and which require CTS to send. They are perhaps a bit
broken and require some CSMA-alike retransmissions etc.

I don't know if one can expect RTS to stay low all the time. Even
a simple /sbin/setserial from /etc/rc.* would drive it high for
a moment. I'm afraid the only way which makes sense may be using
a customized plug.
--
Krzysztof Halasa
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