[ot][spam][crazy] muse-lsl bleak work

[Undiscussed Horrific Abuse, One Victim of Many]

- the chip performs either SPI or UART communication based on a jumper
set during powerup, so if my internet is uninterrupted then it's still
doing UART, and is likely hardwired to always do uart. [spi and uart
are different serial protocols. the kernel driver is offering uart.]
- there are separate pcm and i2s pins for transferring audio data;
these are configured via uart
- the uart auto-detects baud rates up to 4Mbps. the baud rate can also
be configured via a command in the old baud
- > The UART supports the Bluetooth 5.0 UART HCI specification: H4, a
custom Extended H4, and H5. The default baud rate is 115.2 Kbaud.

Further text:
> The UART supports the 3-wire H5 UART transport, as described in the Bluetooth specification (Three-wire UART Transport Layer).
> Compared to H4, the H5 UART transport reduces the number of signal lines required by eliminating the CTS and RTS signals.
> The CYW43455 UART can perform XON/XOFF flow control and includes hardware support for the Serial Line Input Protocol (SLIP).
> It can also perform wake-on activity. For example, activity on the RX or CTS inputs can wake the chip from a sleep state.

I think it makes sense to observe the serial traffic in software now.
It's behaving as if there's no reply at all, which implies the baud
could be somehow wrong, I suppose. Not sure.