Does that framing even have a real official name? It’s usually handwaved around as “async serial” or “UART”.
And remember, with whatever it’s called, in addition to sending characters of various bit lengths, you can send a “break”.
And remember, with whatever it’s called, in addition to sending characters of various bit lengths, you can send a “break”.
UARTs are called universal because they can be configured to work with "any" asynchronous serial protocol (within their bounds), which usually means
- 1 start bit
- 5-9 data bits
- even or odd parity
- 1-2 or sometimes 3 stop bits
per frame. Hardware UARTs also typically oversample 16x, which is why simple software UARTs are often somewhat glitchy.
Split each byte in 4-bit nibbles and used the remaining data bit for not-quite-in-band-signalling.
The Wikipedia article [0] calls this category “asynchronous start-stop signaling” but has no source.
I guess the best term is “UART protocol”, despite the limited size of the “universe”, since it’s really just a de facto convention established by decades of chips called “UARTs”.
[0] https://en.wikipedia.org/wiki/Asynchronous_serial_communicat...