We do serial differently.

[Ian Lepore]

On Thu, 2017-10-19 at 00:25 -0400, Zaphod Beeblebrox wrote:
> How does FreeBSD do serial differently than Linux or MacOS or Windows?
> 
> Now... this isn't _exactly_ serial, but the serial that is emulated by the
> arduino driver in ports.
> 
> The issue is that running the arduino IDE works (and it boots with the
> loaded code), but then running 'pronterface'  fails to connect --- looking
> all-the-while like one-way communication.
> 
> I see someone else basically having the same problem and claiming that
> hacking a trace (that affects the DTR response) on the arduino fixes it for
> FreeBSD (see https://plus.google.com/+MiroslavPrymek/posts/6TDdbuoNhzH )...
> 
> Given this information, can I stty my way out of this problem?  Can I make
> a small modification to pronterface?

Use the "callout" device, /dev/cuaXX, rather than /dev/ttyXX (which is
the "callin" device).  The callin device waits for a call to come in,
and that's implemented by blocking in open() until the modem/other-end
asserts DTR (or DSR, I can never remember which end is which).

So if it's hanging with /dev/ttyU0 use /dev/cuaU0.

-- Ian