On Thu, 31 Oct 2024, John Ogness wrote: > >> THRE only signals there is a space for one character. > > > > Nope[1]: > > > > "In the FIFO mode, THRE is set when the transmit FIFO is empty; it is > > cleared when at least one byte is written to the transmit FIFO." > > > > It seems common enough a misconception that once I actually had to fix the > > bad interpretation of THRE in an unpublished platform driver to get decent > > performance out of it at higher rates such as 230400bps, as it only pushed > > one byte at a time to the FIFO while it had it all available once THRE has > > been set. > > I do not know if this is true for all 8250-variants. If there is some > variant where it functions as Jiri expected, then it would mean > significant text loss during longer messages. But that would already be > a problem in the current mainline driver. Or rather in my case it would prevent communication from working at all; I actually had to fix the issue for networking over a serial line rather than just exchanging text messages, and hence a particular need to make it run fast. I don't expect any 550 clone to work in a different manner, but I find the TI manual particularly unambiguous and well-written, and also old enough for the 550 to be the state of the art rather than just legacy. Maciej
