Re: RPI3 serlial clock confusion?

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Fri, Jul 10, 2020 at 10:15:09AM -0700, Michael Cheponis wrote:
> Thank you.
> 
> It's completely unclear to me, though, why we'd want to use the 'mini UART'
> vs the Main uart, because when we use the mini uart, *we have no access to
> the regular uart via the rpi pins*.  https://elinux.org/RPi_BCM2835_GPIOs
> see how the 40 pins on the connector are mapped, with alternates.

We (and others) use the mini uart for console on RPI3 to keep the
real UART for bluetooth. The mini uart has a limited FIFO, which
means you cannot run bluetooth at best speed. It would also be
subject to the changes in the core frequencies like the console is
now.

You can chose what you want to get:

- have problems with serial console, that's the default
- have problems with bluetooth
- run on fixed frequency

You can use settings in config.txt and/or load a DTB overlay to
select this.  So there are only two questions, what should be the
default and how easy is it for a user to do this configuration.


Greetings,