Re: BeagleBone Black doesn't boot without serial console (10.0 release)

[Christoph Badura <bad%bsd.de@localhost>]

On Fri, Oct 11, 2024 at 06:18:32PM +0100, Robert Swindells wrote:
> 
> Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
> > What does "serial" mean here?  All the USB-to-serial devices I've seen
> > have, I _think_, been RS-232 in everything except the connector
> > (they're typically DE-9 instead of DB-25).
> 
> This:
> <https://thepihut.com/products/usb-to-ttl-serial-cable-debug-console-cable-for-raspberry-pi>
> or this:
> <https://pine64.com/product/serial-console-woodpecker-edition/>
> They are relatively new, FTDI was only founded in 1992.

Even before that the serial IO ICs like the Intel 8250 UART or the Zilog
SIO did, of course, have TTL in- and outputs.  They were usually connected
to MC1488/MC1489 (and later MAX232) transceivers to convert to/from
TIA-232 levels.

Of course, one could directly connect the TTL pins to have two such chips
talk directly to each other.  But that wouldn't have worked or talking to
terminals.

--chris