boot loader serial console speed to 9600

[Ian Lepore]

On Thu, 2018-10-25 at 18:28 +0300, Stefan Parvu wrote:
> > 
> > The ability to change serial console speed from loader(8) only
> > works
> > with x86 BIOS calls (and maybe UEFI, not sure). In general, when
> > uboot
> > is involved, loader will use whatever serial speed was set up by
> > uboot.
> ok, right. Thats exactly probable what we are seeing. We are using a
> RBPI3B+ with Strato Base [1] which connects to a Vaisala logger [2]
> which cannot speak 115200 due its restrictions to operate on solar
> panels etc.
> So we are experimenting with FreeBSD 12 on this setup to fetch data
> from
> the Vaisala logger. 
> 
> > 
> > Why do you want to set the console to such a slow speed? It
> > actually
> > pisses me off that the standard is as slow as 115200 in the 21st
> > century; modern uart chips have no problem running at speeds in the
> > 1-
> > 12mbps range.
> Because I need to connect the Vaisala logger (which cannot speak
> 115200) 
> to the RBPI3B+ to read data. Using a FDTI cable is simple and
> probable will
> work for us.
> 
> Is there anything else we could try to configure ? You mean we could
> configure
> the uboot module ? How ? Any pointers ?
> 
> Thanks a lot for tips,
> Stefan
> 
> [1] https://www.sferalabs.cc/strato-pi/#models
> <https://www.sferalabs.cc/strato-pi/#models>
> [2] https://www.vaisala.com/sites/default/files/documents/QML201C-Dat
> asheet-B210718EN.pdf
> <https://www.vaisala.com/sites/default/files/documents/QML201C-
> Datasheet-B210718EN.pdf> 

Normally you set a uboot env var named "baudrate".  If you do it
interactively, it will prompt you to change your terminal program rate
to the new value then hit enter.  If you do saveenv it'll just run at
that speed from startup on future boots.

But, everything about RPi is non-standard, so probably none of that
works, in which case you'll have to hunt around for the rpi way of
doing the same thing.

I would think if you're emitting data to a logger via uart, you would
want to disable the serial console completely, so that your data
generating application can have exclusive use of the uart to output
data.

-- Ian