On Sun, 2 Feb 2025, Chuck Guzis via cctalk wrote:
> > I forgot to mention: MIDI has been another notable example where you want
> > to wire a UART to another kind of line driver. I also have a computer
> > where one of USARTs is multiplexed (software-configurable) between an
> > RS-232 line driver with an external DE-9 connector (with pins multiplexed
> > between synchronous-mode TxC/RxC clock lines and asynchronous-mode CTS/DSR
> > inputs respectively) and an AC'97 audio codec (the codec uses the USART's
> > synchronous mode with internal clocking). This one obviously also uses
> > regular voltage levels to talk to the AC'97 device.
>
> Except that MIDI is a current-driven interface, not voltage like RS232.
> 5 ma currentloop, if memory serves.Voltage is secondary.
Sure, I just gave it as another example that you can wire a UART that
uses TTL or other standard digital circuit signalling to different line
drivers ("phys"). It all boils down to the application.
Maciej
