Serial Cable for booting FreeBSD on the BeagleBone Black

[Tim Kientzle]

> On Dec 30, 2016, at 2:16 PM, Dr. Rolf Jansen <rj at obsigna.com> wrote:
> 
> I ordered my BeagleBone Black, and I will receive it next week.
> 
> I read on https://wiki.freebsd.org/FreeBSD/arm/BeagleBoneBlack about booting the BBB with FreeBSD, that I need to:
> 
>   "Connect a serial cable such as the FTDI TTL-232R 3.3v
>    or the Adafruit 4-pin cable"
> 
> I am sorry, for needing to ask the obvious:
> 
> - connect the serial cable to where and for what purpose?

If you're using a pre-built image, you may not need a serial cable.
But if you want to build your own image or otherwise tinker with
the system, you will likely need it at some point.

On the BBB, not all boot messages appear on the video
output.  In particular, the very early boot messages only appear
on the "serial console" where you can only see them from
another machine connected via serial cable.

Without a serial cable, it is extremely challenging to diagnose
boot problems.

> - what is required on the other end for establishing the
>  facility which the BBB needs for booting?

If your host machine is running FreeBSD, you can use the
'tip' or 'cu' programs (these are part of FreeBSD base system).

For other systems, just search for "bbb serial console XYZ" (where XYZ
is your preferred host system, e.g., Linux, Windows, or macOS).

> - none of my machines got a RS232 connector, I even can't
>  remember when I dropped out the last one that got RS232.

The cable mentioned above connects to USB on the host machine,
so you don't need an RS-232 connector.

Tim