MIME-Version: 1.0
Message-ID: <trinity-830152b7-3225-49e3-860f-795030d68481-1717504956323@3c-app-mailcom-bs13>
From: Iulian Tocu <itocu@gmx.com>
To: ~alpine/users@lists.alpinelinux.org
Subject: accessing ttyS0 or ttyUSB0
Content-Type: text/plain; charset=UTF-8
Date: Tue, 4 Jun 2024 14:42:36 +0200
Importance: normal
Sensitivity: Normal
UI-OutboundReport: notjunk:1;M01:P0:iVvcs6dy16M=;tg5OHl0gTJAcPl9WKlaD4sRq6lN
 ySoUqfFxJrH1l6VtgBnn2tsjPAy/BW7g1AjGoTVFTSs7u2WUJXDsQ8oSvf+9IH9eUyXbjDvPH
 Gjq7lbdXoyX+DGGeJQWaCDJTVXIUU1LzmnzuSHic8F+q5PnsmyWjtMQi2kSbFDSkfrgo6kR69
 nyOz6J+FYKSulaJKw+Kek0IjxMWR+gNnx2N1akr5oDuOVoKF3ISFJPaVz1PJr5toAZnXXyuCO
 ODM2mb5C8NcEgcHFM1C2+K82vwtRjnh3mCWfPKfIjbmZsXDxVvdFHm6IfY2U6693PDF8uBahl
 +/S23Npxjdz4yzp9BCuwKeNDDo0HxtQizEQybsPTACnH6U1Z9+VtgHgUWOwubmuRzrV0Cpknj
 bsO4Lpv/WJYg6kjnacCXZw3/IGL6PlY6TWF2yPHuZuNKjgdHkpoJlhP14BXzhoBenenjmYH8T
 z/f0seYGUA199HYdxbHHNyD0P+5AgATJKjsqdcP2cVS4YzdFVRHZnTE31fg3zR8bx7dLyeW6k
 78DOnkRmbxLRA3n+VwlarQVOUgKT7XLjFgsV073MT5KbmoZGvT801HwwudO5kIncW3AwLDJYZ
 zSi42pRHw+6vj+aNDl5FLUXXbt2PCdKYweq0DagnyhFUKpQ/BIWhzOroQrGa/I1ZATBV+35Uh
 KG3Ki+5Xu283rwSLuHNq2rBqpj+uNcNL1QREIxXh6qmEhyi5A0T+a3w2knu78ic=
Content-Transfer-Encoding: quoted-printable


Hi all,

I'm trying to access a serial console of a different system. Let's
call it the target system. This target system has the boot handled
by u-boot and I need to stop it at its countdown and enter some
boot options. The target system has the u-boot console over
the serial line and it's connected to my host machine with
an old serial cable to the COM0 port.
In the past, I had a live Linux that I was using to start host
machine and I remember I was happy with "screen /dev/ttyS0 115200".
Today, I've installed Alpine Linux v3.20 32-bit to my host machine
(install mode: sys) and I see strange output from my target system
no matter if I'm using mincom ("minicom -D /dev/ttyS0 -b 115200")
or screen.
It looks like the line feed or some settings are not correct on
this serial line. So I've started to play with some stty commands
but I didn't find a proper configuration for my ttyS0.
Also I'm not able to enter any commands (or stop the u-boot).
Next, I've brought in my host system an USB-to-serial dongle and
switch my attempts to /dev/ttyUSB0 but again without success. Same
output problem, same ignored-input problem.
I noticed that my settings set by stty are also changing back somehow.
So beside the usual 115200/8/N/1, I think I'm missing something.
Do you have any hints for me to find the proper way?

Thanks!
Iulian