Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 19 Oct 2017 20:22:46 +0300
From:      Konstantin Belousov <kostikbel@gmail.com>
To:        Ian Lepore <ian@freebsd.org>
Cc:        Zaphod Beeblebrox <zbeeble@gmail.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org>
Subject:   Re: We do serial differently.
Message-ID:  <20171019172246.GU2473@kib.kiev.ua>
In-Reply-To: <1508432312.1383.18.camel@freebsd.org>
References:  <CACpH0Md0ckYH6k5ufAwCoc-_ThtJHrV9%2BdUtp66%2BSSjVuyhpxA@mail.gmail.com> <1508425713.1383.6.camel@freebsd.org> <CACpH0MfaP%2B0BY-1VqbnTQXe9xtLpU3%2BopYaNpRQC1so0C5iKmw@mail.gmail.com> <1508432312.1383.18.camel@freebsd.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Oct 19, 2017 at 10:58:32AM -0600, Ian Lepore wrote:
> Note that that really describes the tty-layer behavior, it's what tells
> the ftdi chip to turn dtr on and off, so it should apply to other
> brands of usb adapter as well.
> 
> Looking at that page you cited in your original message and how it
> talks about a dtr connection to reset, this might be the problem. šYou
> can try "stty -f /dev/cuaU0 -hupcl" -- that will force the signal to be
> driven low continuously, regardless of whether anyone has the device
> open or not. šBut there's no telling if that's the right behavior for
> your arduino, it might just be differently-wrong, like never doing the
> reset at all. šIf the line needs to be pulsed to do a reset maybe you
> can use a wrapper script that does stty hupcl; sleep .1; stty -hupcl,
> then launches your program.

For each tty device, including cuaU*, there are <name>.init and <name>.lock
devfs nodes which can be used to set the initial and permanent states of
the flags.  It might be useful in this situation.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20171019172246.GU2473>