i386/105616: UART PCI device just silent...

Helge Oldach puc-uart at oldach.net
Tue Nov 28 08:30:19 PST 2006


The following reply was made to PR i386/105616; it has been noted by GNATS.

From: puc-uart at oldach.net (Helge Oldach)
To: xcllnt at mac.com (Marcel Moolenaar)
Cc: FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: i386/105616: UART PCI device just silent...
Date: Tue, 28 Nov 2006 17:21:43 +0100 (CET)

 Hi Marcel,
 
 >> If it helps, I can place this card in a test machine over here for a
 >> couple of days and plug some serial device to it, so that you can play
 >> with it from remote. That may take a day or two to set up however.
 >
 >That would definitely help. If you have a cross-over cable then you
 >can connect both UART interfaces with each other,
 
 Thats a good point. I tried this with the current machine - and it
 works! I'm completely astonished. I can send characters in either
 direction. Both lines are stty clocal -crtcts (as it should with cu), so
 there is likely no hardware flow control issue.
 
 I rewired the line to the Cisco router with a LED box inbetween - and I
 see both RX and TX flicker when I send characters from the appropriate
 direction. So data is clearly transmitted. Again, control signals are
 fine.
 
 I cross-checked this with the sio kernel - exactly the same control
 signals, exactly the same behaviour.
 
 The only thing that may be botched is speed, or potentially also parity
 or stop bits. Again I iterated all possible speeds and also played
 around with parity & stop bits on the Cisco end, but no success. I
 suspect that with the cross-over cable bith UARTs have some arbitrary,
 non-common clocking so that it works in that scenario.
 
 Any ideas?
 
 Helge


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