Subject: Re: belkin usb serial converter (mct_u232), break not working
From: Paul Fulghum <paulkf@microgate.com>
To: Thomas Stewart <thomas@stewarts.org.uk>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
In-Reply-To: <200410201946.35514.thomas@stewarts.org.uk>
References: <200410201946.35514.thomas@stewarts.org.uk>
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Message-Id: <1098305293.2818.2.camel@deimos.microgate.com>
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Date: Wed, 20 Oct 2004 15:48:13 -0500
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On Wed, 2004-10-20 at 13:46, Thomas Stewart wrote:
> Hi,
> 
> I'm having trouble with a Belkin USB serial adapter, I can't get it to send a 
> break down the serial cable to a console.
> 
> I made a quick program to send a break to a port (mostly ripped off from 
> minicom). 
> 
> porttest.c:
> #include <sys/fcntl.h>
> #include <sys/ioctl.h>
> main () {
>         int fd = open("/dev/ttyS0", O_RDWR|O_NOCTTY);
>         ioctl(fd, TCSBRK, 0);
>         close(fd);
> }
> 
> Both minicom and my program send a break fine to a regular pc serial port (eg 
> ttyS0). In this case it drops my sun box to an "ok" prompt.
> 
> However if I use the usb serial adapter both minicom and my program are unable 
> to send breaks, they just seem to get ignored.

Could this be a simple matter of timing?

The Sun box may require a break for a certain period
which by chance is met on a standard UART but not
the USB serial adapter.

Try adding a sleep() after the ioctl call to delay
before clearing the break condition.

-- 
Paul Fulghum
paulkf@microgate.com

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